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  • ASP.NET Web API Exception Handling

    - by Fredrik N
    When I talk about exceptions in my product team I often talk about two kind of exceptions, business and critical exceptions. Business exceptions are exceptions thrown based on “business rules”, for example if you aren’t allowed to do a purchase. Business exceptions in most case aren’t important to log into a log file, they can directly be shown to the user. An example of a business exception could be "DeniedToPurchaseException”, or some validation exceptions such as “FirstNameIsMissingException” etc. Critical Exceptions are all other kind of exceptions such as the SQL server is down etc. Those kind of exception message need to be logged and should not reach the user, because they can contain information that can be harmful if it reach out to wrong kind of users. I often distinguish business exceptions from critical exceptions by creating a base class called BusinessException, then in my error handling code I catch on the type BusinessException and all other exceptions will be handled as critical exceptions. This blog post will be about different ways to handle exceptions and how Business and Critical Exceptions could be handled. Web API and Exceptions the basics When an exception is thrown in a ApiController a response message will be returned with a status code set to 500 and a response formatted by the formatters based on the “Accept” or “Content-Type” HTTP header, for example JSON or XML. Here is an example:   public IEnumerable<string> Get() { throw new ApplicationException("Error!!!!!"); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The response message will be: HTTP/1.1 500 Internal Server Error Content-Length: 860 Content-Type: application/json; charset=utf-8 { "ExceptionType":"System.ApplicationException","Message":"Error!!!!!","StackTrace":" at ..."} .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The stack trace will be returned to the client, this is because of making it easier to debug. Be careful so you don’t leak out some sensitive information to the client. So as long as you are developing your API, this is not harmful. In a production environment it can be better to log exceptions and return a user friendly exception instead of the original exception. There is a specific exception shipped with ASP.NET Web API that will not use the formatters based on the “Accept” or “Content-Type” HTTP header, it is the exception is the HttpResponseException class. Here is an example where the HttpReponseExcetpion is used: // GET api/values [ExceptionHandling] public IEnumerable<string> Get() { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError)); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The response will not contain any content, only header information and the status code based on the HttpStatusCode passed as an argument to the HttpResponseMessage. Because the HttpResponsException takes a HttpResponseMessage as an argument, we can give the response a content: public IEnumerable<string> Get() { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("My Error Message"), ReasonPhrase = "Critical Exception" }); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   The code above will have the following response:   HTTP/1.1 500 Critical Exception Content-Length: 5 Content-Type: text/plain; charset=utf-8 My Error Message .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The Content property of the HttpResponseMessage doesn’t need to be just plain text, it can also be other formats, for example JSON, XML etc. By using the HttpResponseException we can for example catch an exception and throw a user friendly exception instead: public IEnumerable<string> Get() { try { DoSomething(); return new string[] { "value1", "value2" }; } catch (Exception e) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("An error occurred, please try again or contact the administrator."), ReasonPhrase = "Critical Exception" }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Adding a try catch to every ApiController methods will only end in duplication of code, by using a custom ExceptionFilterAttribute or our own custom ApiController base class we can reduce code duplicationof code and also have a more general exception handler for our ApiControllers . By creating a custom ApiController’s and override the ExecuteAsync method, we can add a try catch around the base.ExecuteAsync method, but I prefer to skip the creation of a own custom ApiController, better to use a solution that require few files to be modified. The ExceptionFilterAttribute has a OnException method that we can override and add our exception handling. Here is an example: using System; using System.Diagnostics; using System.Net; using System.Net.Http; using System.Web.Http; using System.Web.Http.Filters; public class ExceptionHandlingAttribute : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { if (context.Exception is BusinessException) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(context.Exception.Message), ReasonPhrase = "Exception" }); } //Log Critical errors Debug.WriteLine(context.Exception); throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent("An error occurred, please try again or contact the administrator."), ReasonPhrase = "Critical Exception" }); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   Note: Something to have in mind is that the ExceptionFilterAttribute will be ignored if the ApiController action method throws a HttpResponseException. The code above will always make sure a HttpResponseExceptions will be returned, it will also make sure the critical exceptions will show a more user friendly message. The OnException method can also be used to log exceptions. By using a ExceptionFilterAttribute the Get() method in the previous example can now look like this: public IEnumerable<string> Get() { DoSomething(); return new string[] { "value1", "value2" }; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To use the an ExceptionFilterAttribute, we can for example add the ExceptionFilterAttribute to our ApiControllers methods or to the ApiController class definition, or register it globally for all ApiControllers. You can read more about is here. Note: If something goes wrong in the ExceptionFilterAttribute and an exception is thrown that is not of type HttpResponseException, a formatted exception will be thrown with stack trace etc to the client. How about using a custom IHttpActionInvoker? We can create our own IHTTPActionInvoker and add Exception handling to the invoker. The IHttpActionInvoker will be used to invoke the ApiController’s ExecuteAsync method. Here is an example where the default IHttpActionInvoker, ApiControllerActionInvoker, is used to add exception handling: public class MyApiControllerActionInvoker : ApiControllerActionInvoker { public override Task<HttpResponseMessage> InvokeActionAsync(HttpActionContext actionContext, System.Threading.CancellationToken cancellationToken) { var result = base.InvokeActionAsync(actionContext, cancellationToken); if (result.Exception != null && result.Exception.GetBaseException() != null) { var baseException = result.Exception.GetBaseException(); if (baseException is BusinessException) { return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(baseException.Message), ReasonPhrase = "Error" }); } else { //Log critical error Debug.WriteLine(baseException); return Task.Run<HttpResponseMessage>(() => new HttpResponseMessage(HttpStatusCode.InternalServerError) { Content = new StringContent(baseException.Message), ReasonPhrase = "Critical Error" }); } } return result; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } You can register the IHttpActionInvoker with your own IoC to resolve the MyApiContollerActionInvoker, or add it in the Global.asax: GlobalConfiguration.Configuration.Services.Remove(typeof(IHttpActionInvoker), GlobalConfiguration.Configuration.Services.GetActionInvoker()); GlobalConfiguration.Configuration.Services.Add(typeof(IHttpActionInvoker), new MyApiControllerActionInvoker()); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   How about using a Message Handler for Exception Handling? By creating a custom Message Handler, we can handle error after the ApiController and the ExceptionFilterAttribute is invoked and in that way create a global exception handler, BUT, the only thing we can take a look at is the HttpResponseMessage, we can’t add a try catch around the Message Handler’s SendAsync method. The last Message Handler that will be used in the Wep API pipe-line is the HttpControllerDispatcher and this Message Handler is added to the HttpServer in an early stage. The HttpControllerDispatcher will use the IHttpActionInvoker to invoke the ApiController method. The HttpControllerDipatcher has a try catch that will turn ALL exceptions into a HttpResponseMessage, so that is the reason why a try catch around the SendAsync in a custom Message Handler want help us. If we create our own Host for the Wep API we could create our own custom HttpControllerDispatcher and add or exception handler to that class, but that would be little tricky but is possible. We can in a Message Handler take a look at the HttpResponseMessage’s IsSuccessStatusCode property to see if the request has failed and if we throw the HttpResponseException in our ApiControllers, we could use the HttpResponseException and give it a Reason Phrase and use that to identify business exceptions or critical exceptions. I wouldn’t add an exception handler into a Message Handler, instead I should use the ExceptionFilterAttribute and register it globally for all ApiControllers. BUT, now to another interesting issue. What will happen if we have a Message Handler that throws an exception?  Those exceptions will not be catch and handled by the ExceptionFilterAttribute. I found a  bug in my previews blog post about “Log message Request and Response in ASP.NET WebAPI” in the MessageHandler I use to log incoming and outgoing messages. Here is the code from my blog before I fixed the bug:   public abstract class MessageHandler : DelegatingHandler { protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { var corrId = string.Format("{0}{1}", DateTime.Now.Ticks, Thread.CurrentThread.ManagedThreadId); var requestInfo = string.Format("{0} {1}", request.Method, request.RequestUri); var requestMessage = await request.Content.ReadAsByteArrayAsync(); await IncommingMessageAsync(corrId, requestInfo, requestMessage); var response = await base.SendAsync(request, cancellationToken); var responseMessage = await response.Content.ReadAsByteArrayAsync(); await OutgoingMessageAsync(corrId, requestInfo, responseMessage); return response; } protected abstract Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message); protected abstract Task OutgoingMessageAsync(string correlationId, string requestInfo, byte[] message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; }   If a ApiController throws a HttpResponseException, the Content property of the HttpResponseMessage from the SendAsync will be NULL. So a null reference exception is thrown within the MessageHandler. The yellow screen of death will be returned to the client, and the content is HTML and the Http status code is 500. The bug in the MessageHandler was solved by adding a check against the HttpResponseMessage’s IsSuccessStatusCode property: public abstract class MessageHandler : DelegatingHandler { protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { var corrId = string.Format("{0}{1}", DateTime.Now.Ticks, Thread.CurrentThread.ManagedThreadId); var requestInfo = string.Format("{0} {1}", request.Method, request.RequestUri); var requestMessage = await request.Content.ReadAsByteArrayAsync(); await IncommingMessageAsync(corrId, requestInfo, requestMessage); var response = await base.SendAsync(request, cancellationToken); byte[] responseMessage; if (response.IsSuccessStatusCode) responseMessage = await response.Content.ReadAsByteArrayAsync(); else responseMessage = Encoding.UTF8.GetBytes(response.ReasonPhrase); await OutgoingMessageAsync(corrId, requestInfo, responseMessage); return response; } protected abstract Task IncommingMessageAsync(string correlationId, string requestInfo, byte[] message); protected abstract Task OutgoingMessageAsync(string correlationId, string requestInfo, byte[] message); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } If we don’t handle the exceptions that can occur in a custom Message Handler, we can have a hard time to find the problem causing the exception. The savior in this case is the Global.asax’s Application_Error: protected void Application_Error() { var exception = Server.GetLastError(); Debug.WriteLine(exception); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } I would recommend you to add the Application_Error to the Global.asax and log all exceptions to make sure all kind of exception is handled. Summary There are different ways we could add Exception Handling to the Wep API, we can use a custom ApiController, ExceptionFilterAttribute, IHttpActionInvoker or Message Handler. The ExceptionFilterAttribute would be a good place to add a global exception handling, require very few modification, just register it globally for all ApiControllers, even the IHttpActionInvoker can be used to minimize the modifications of files. Adding the Application_Error to the global.asax is a good way to catch all unhandled exception that can occur, for example exception thrown in a Message Handler.   If you want to know when I have posted a blog post, you can follow me on twitter @fredrikn

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  • Deploy ASP.NET Web Applications with Web Deployment Projects

    - by Ben Griswold
    One may quickly build and deploy an ASP.NET web application via the Publish option in Visual Studio.  This option works great for most simple deployment scenarios but it won’t always cut it.  Let’s say you need to automate your deployments. Or you have environment-specific configuration settings. Or you need to execute pre/post build operations when you do your builds.  If so, you should consider using Web Deployment Projects. The Web Deployment Project type doesn’t come out-of-the-box with Visual Studio 2008.  You’ll need to Download Visual Studio® 2008 Web Deployment Projects – RTW and install if you want to follow along with this tutorial. I’ve created a shiny new ASP.NET MVC project.  Web Deployment Projects work with websites, web applications and MVC projects so feel free to go with any web project type you’d like.  Once your web application is in place, it’s time to add the Web Deployment project.  You can hunt and peck around the File > New > New Project… dialogue as long as you’d like, but you aren’t going to find what you need.  Instead, select the web project and then choose the “Add Web Deployment Project…” hiding behind the Build menu option. I prefer to name my projects based on the environment in which I plan to deploy.  In this case, I’ll be rolling to the QA machine. Don’t expect too much to happen at this point.  A seemingly empty project with a funny icon will be added to your solution.  That’s it. I want to take a minute and talk about configuration settings before we continue.  Some of the common settings which might change from environment to environment are appSettings, connectionStrings and mailSettings.  Here’s a look at my updated web.config: <appSettings>   <add key="MvcApplication293.Url" value="http://localhost:50596/" />     </appSettings> <connectionStrings>   <add name="ApplicationServices"        connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true"        providerName="System.Data.SqlClient"/> </connectionStrings>   <system.net>   <mailSettings>     <smtp from="[email protected]">         <network host="server.com" userName="username" password="password" port="587" defaultCredentials="false"/>     </smtp>   </mailSettings> </system.net> I want to update these values prior to deploying to the QA environment.  There are variations to this approach, but I like to maintain environment-specific settings for each of the web.config sections in the Config/[Environment] project folders.  I’ve provided a screenshot of the QA environment settings below. It may be obvious what one should include in each of the three files.  Basically, it is a copy of the associated web.config section with updated setting values.  For example, the AppSettings.config file may include a reference to the QA web url, the DB.config would include the QA database server and login information and the StmpSettings.config would include a QA Stmp server and user information. <?xml version="1.0" encoding="utf-8" ?> <appSettings>   <add key="MvcApplication293.Url" value="http://qa.MvcApplicatinon293.com/" /> </appSettings> AppSettings.config  <?xml version="1.0" encoding="utf-8" ?> <connectionStrings>   <add name="ApplicationServices"        connectionString="server=QAServer;integrated security=SSPI;database=MvcApplication293"        providerName="System.Data.SqlClient"/>   </connectionStrings> Db.config  <?xml version="1.0" encoding="utf-8" ?> <smtp from="[email protected]">     <network host="qaserver.com" userName="qausername" password="qapassword" port="587" defaultCredentials="false"/> </smtp> SmtpSettings.config  I think our web project is ready to deploy.  Now, it’s time to concentrate on the Web Deployment Project itself.  Right-click on the project file and open the Property Pages. The first thing to call out is the Configuration dropdown.  I only deploy a project which is built in Release Mode so I only setup the Web Deployment Project for this mode.  (This is when you change the Configuration selection to “Release.”)  I typically keep the Output Folder default value – .\Release\.  When the application is built, all artifacts will be dropped in the .\Release\ folder relative to the Web Deployment Project root.  The final option may be up for some debate.  I like to roll out updatable websites so I select the “Allow this precompiled site to be updatable” option.  I really do like to follow standard SDLC processes when I release my software but there are those times when you just have to make a hotfix to production and I like to keep this option open if need be.  If you are strongly opposed to this idea, please, by all means, don’t check the box. The next tab is boring.  I don’t like to deploy a crazy number of DLLs so I merge all outputs to a single assembly.  Again, you may have another option and feel free to change this selection if you so wish. If you follow my lead, take care when choosing a single assembly name.  The Assembly Name can not be the same as the website or any other project in your solution otherwise you’ll receive a circular reference build error.  In other words, I can’t name the assembly MvcApplication293 or my output window would start yelling at me. Remember when we called out our QA configuration files?  Click on the Deployment tab and you’ll see how where going to use them.  Notice the Web.config file section replacements value.  All this does is swap called out web.config sections with the content of the Config\QA\* files.  You can reduce or extend this list as you deem fit.  Did you see the “Use external configuration source file” option?  You know how you can point any of your web.config sections to an external file via the configSource attribute?  This option allows you to leverage that technique and instead of replacing the content of the sections, you will replace the configSource attribute value instead. <appSettings configSource="Config\QA\AppSettings.config" /> Go ahead and Apply your changes.  I’d like to take a look at the project file we just updated.  Right-click on the Web Deployment Project and select “Open Project File.” One of the first configuration blocks reflects core Release build settings.  There are a couple of points I’d like to call out here: DebugSymbols=false ensures the compilation debug attribute in your web.config is flipped to false as part of build process.  There’s some crumby (more likely old) documentation which implies you need a ToggleDebugCompilation task to make this happen.  Nope. Just make sure the DebugSymbols is set to false.  EnableUpdateable implies a single dll for the web application rather than a dll for each object and and empty view file. I think updatable applications are cleaner and include the benefit (or risk based on your perspective) that portions of the application can be updated directly on the server.  I called this out earlier but I wanted to reiterate. <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">     <DebugSymbols>false</DebugSymbols>     <OutputPath>.\Release</OutputPath>     <EnableUpdateable>true</EnableUpdateable>     <UseMerge>true</UseMerge>     <SingleAssemblyName>MvcApplication293</SingleAssemblyName>     <DeleteAppCodeCompiledFiles>true</DeleteAppCodeCompiledFiles>     <UseWebConfigReplacement>true</UseWebConfigReplacement>     <ValidateWebConfigReplacement>true</ValidateWebConfigReplacement>     <DeleteAppDataFolder>true</DeleteAppDataFolder>   </PropertyGroup> The next section is self-explanatory.  The content merely reflects the replacement value you provided via the Property Pages. <ItemGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'">     <WebConfigReplacementFiles Include="Config\QA\AppSettings.config">       <Section>appSettings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\Db.config">       <Section>connectionStrings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\SmtpSettings.config">       <Section>system.net/mailSettings/smtp</Section>     </WebConfigReplacementFiles>   </ItemGroup> You’ll want to extend the ItemGroup section to include the files you wish to exclude from the build.  The sample ExcludeFromBuild nodes exclude all obj, svn, csproj, user, pdb artifacts from the build. Enough though they files aren’t included in your web project, you’ll need to exclude them or they’ll show up along with required deployment artifacts.  <ItemGroup Condition="'$(Configuration)|$(Platform)' == 'Release|AnyCPU'">     <WebConfigReplacementFiles Include="Config\QA\AppSettings.config">       <Section>appSettings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\Db.config">       <Section>connectionStrings</Section>     </WebConfigReplacementFiles>     <WebConfigReplacementFiles Include="Config\QA\SmtpSettings.config">       <Section>system.net/mailSettings/smtp</Section>     </WebConfigReplacementFiles>     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\obj\**\*.*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\.svn\**\*.*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\.svn\**\*" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\*.csproj" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\**\*.user" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\bin\*.pdb" />     <ExcludeFromBuild Include="$(SourceWebPhysicalPath)\Notes.txt" />   </ItemGroup> Pre/post build and Pre/post merge tasks are added to the final code block.  By default, your project file should look like the following – a completely commented out section. <!– To modify your build process, add your task inside one of        the targets below and uncomment it. Other similar extension        points exist, see Microsoft.WebDeployment.targets.   <Target Name="BeforeBuild">   </Target>   <Target Name="BeforeMerge">   </Target>   <Target Name="AfterMerge">   </Target>   <Target Name="AfterBuild">   </Target>   –> Update the section to remove all temporary Config folders and files after the build.  <!– To modify your build process, add your task inside one of        the targets below and uncomment it. Other similar extension        points exist, see Microsoft.WebDeployment.targets.     <Target Name="BeforeMerge">   </Target>   <Target Name="AfterMerge">   </Target>     <Target Name="BeforeBuild">      </Target>       –>   <Target Name="AfterBuild">     <!– WebConfigReplacement requires the Config files. Remove after build. –>     <RemoveDir Directories="$(OutputPath)\Config" />   </Target> That’s it for setup.  Save the project file, flip the solution to Release Mode and build.  If there’s an issue, consult the Output window for details.  If all went well, you will find your deployment artifacts in your Web Deployment Project folder like so. Both the code source and published application will be there. Inside the Release folder you will find your “published files” and you’ll notice the Config folder is no where to be found.  In the Source folder, all project files are found with the exception of the items which were excluded from the build. I’ll wrap up this tutorial by calling out a little Web Deployment pet peeve of mine: there doesn’t appear to be a way to add an existing web deployment project to a solution.  The best I can come up with is create a new web deployment project and then copy and paste the contents of the existing project file into the new project file.  It’s not a big deal but it bugs me. Download the Solution

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  • Improving Partitioned Table Join Performance

    - by Paul White
    The query optimizer does not always choose an optimal strategy when joining partitioned tables. This post looks at an example, showing how a manual rewrite of the query can almost double performance, while reducing the memory grant to almost nothing. Test Data The two tables in this example use a common partitioning partition scheme. The partition function uses 41 equal-size partitions: CREATE PARTITION FUNCTION PFT (integer) AS RANGE RIGHT FOR VALUES ( 125000, 250000, 375000, 500000, 625000, 750000, 875000, 1000000, 1125000, 1250000, 1375000, 1500000, 1625000, 1750000, 1875000, 2000000, 2125000, 2250000, 2375000, 2500000, 2625000, 2750000, 2875000, 3000000, 3125000, 3250000, 3375000, 3500000, 3625000, 3750000, 3875000, 4000000, 4125000, 4250000, 4375000, 4500000, 4625000, 4750000, 4875000, 5000000 ); GO CREATE PARTITION SCHEME PST AS PARTITION PFT ALL TO ([PRIMARY]); There two tables are: CREATE TABLE dbo.T1 ( TID integer NOT NULL IDENTITY(0,1), Column1 integer NOT NULL, Padding binary(100) NOT NULL DEFAULT 0x,   CONSTRAINT PK_T1 PRIMARY KEY CLUSTERED (TID) ON PST (TID) );   CREATE TABLE dbo.T2 ( TID integer NOT NULL, Column1 integer NOT NULL, Padding binary(100) NOT NULL DEFAULT 0x,   CONSTRAINT PK_T2 PRIMARY KEY CLUSTERED (TID, Column1) ON PST (TID) ); The next script loads 5 million rows into T1 with a pseudo-random value between 1 and 5 for Column1. The table is partitioned on the IDENTITY column TID: INSERT dbo.T1 WITH (TABLOCKX) (Column1) SELECT (ABS(CHECKSUM(NEWID())) % 5) + 1 FROM dbo.Numbers AS N WHERE n BETWEEN 1 AND 5000000; In case you don’t already have an auxiliary table of numbers lying around, here’s a script to create one with 10 million rows: CREATE TABLE dbo.Numbers (n bigint PRIMARY KEY);   WITH L0 AS(SELECT 1 AS c UNION ALL SELECT 1), L1 AS(SELECT 1 AS c FROM L0 AS A CROSS JOIN L0 AS B), L2 AS(SELECT 1 AS c FROM L1 AS A CROSS JOIN L1 AS B), L3 AS(SELECT 1 AS c FROM L2 AS A CROSS JOIN L2 AS B), L4 AS(SELECT 1 AS c FROM L3 AS A CROSS JOIN L3 AS B), L5 AS(SELECT 1 AS c FROM L4 AS A CROSS JOIN L4 AS B), Nums AS(SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) AS n FROM L5) INSERT dbo.Numbers WITH (TABLOCKX) SELECT TOP (10000000) n FROM Nums ORDER BY n OPTION (MAXDOP 1); Table T1 contains data like this: Next we load data into table T2. The relationship between the two tables is that table 2 contains ‘n’ rows for each row in table 1, where ‘n’ is determined by the value in Column1 of table T1. There is nothing particularly special about the data or distribution, by the way. INSERT dbo.T2 WITH (TABLOCKX) (TID, Column1) SELECT T.TID, N.n FROM dbo.T1 AS T JOIN dbo.Numbers AS N ON N.n >= 1 AND N.n <= T.Column1; Table T2 ends up containing about 15 million rows: The primary key for table T2 is a combination of TID and Column1. The data is partitioned according to the value in column TID alone. Partition Distribution The following query shows the number of rows in each partition of table T1: SELECT PartitionID = CA1.P, NumRows = COUNT_BIG(*) FROM dbo.T1 AS T CROSS APPLY (VALUES ($PARTITION.PFT(TID))) AS CA1 (P) GROUP BY CA1.P ORDER BY CA1.P; There are 40 partitions containing 125,000 rows (40 * 125k = 5m rows). The rightmost partition remains empty. The next query shows the distribution for table 2: SELECT PartitionID = CA1.P, NumRows = COUNT_BIG(*) FROM dbo.T2 AS T CROSS APPLY (VALUES ($PARTITION.PFT(TID))) AS CA1 (P) GROUP BY CA1.P ORDER BY CA1.P; There are roughly 375,000 rows in each partition (the rightmost partition is also empty): Ok, that’s the test data done. Test Query and Execution Plan The task is to count the rows resulting from joining tables 1 and 2 on the TID column: SET STATISTICS IO ON; DECLARE @s datetime2 = SYSUTCDATETIME();   SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID;   SELECT DATEDIFF(Millisecond, @s, SYSUTCDATETIME()); SET STATISTICS IO OFF; The optimizer chooses a plan using parallel hash join, and partial aggregation: The Plan Explorer plan tree view shows accurate cardinality estimates and an even distribution of rows across threads (click to enlarge the image): With a warm data cache, the STATISTICS IO output shows that no physical I/O was needed, and all 41 partitions were touched: Running the query without actual execution plan or STATISTICS IO information for maximum performance, the query returns in around 2600ms. Execution Plan Analysis The first step toward improving on the execution plan produced by the query optimizer is to understand how it works, at least in outline. The two parallel Clustered Index Scans use multiple threads to read rows from tables T1 and T2. Parallel scan uses a demand-based scheme where threads are given page(s) to scan from the table as needed. This arrangement has certain important advantages, but does result in an unpredictable distribution of rows amongst threads. The point is that multiple threads cooperate to scan the whole table, but it is impossible to predict which rows end up on which threads. For correct results from the parallel hash join, the execution plan has to ensure that rows from T1 and T2 that might join are processed on the same thread. For example, if a row from T1 with join key value ‘1234’ is placed in thread 5’s hash table, the execution plan must guarantee that any rows from T2 that also have join key value ‘1234’ probe thread 5’s hash table for matches. The way this guarantee is enforced in this parallel hash join plan is by repartitioning rows to threads after each parallel scan. The two repartitioning exchanges route rows to threads using a hash function over the hash join keys. The two repartitioning exchanges use the same hash function so rows from T1 and T2 with the same join key must end up on the same hash join thread. Expensive Exchanges This business of repartitioning rows between threads can be very expensive, especially if a large number of rows is involved. The execution plan selected by the optimizer moves 5 million rows through one repartitioning exchange and around 15 million across the other. As a first step toward removing these exchanges, consider the execution plan selected by the optimizer if we join just one partition from each table, disallowing parallelism: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = 1 AND $PARTITION.PFT(T2.TID) = 1 OPTION (MAXDOP 1); The optimizer has chosen a (one-to-many) merge join instead of a hash join. The single-partition query completes in around 100ms. If everything scaled linearly, we would expect that extending this strategy to all 40 populated partitions would result in an execution time around 4000ms. Using parallelism could reduce that further, perhaps to be competitive with the parallel hash join chosen by the optimizer. This raises a question. If the most efficient way to join one partition from each of the tables is to use a merge join, why does the optimizer not choose a merge join for the full query? Forcing a Merge Join Let’s force the optimizer to use a merge join on the test query using a hint: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (MERGE JOIN); This is the execution plan selected by the optimizer: This plan results in the same number of logical reads reported previously, but instead of 2600ms the query takes 5000ms. The natural explanation for this drop in performance is that the merge join plan is only using a single thread, whereas the parallel hash join plan could use multiple threads. Parallel Merge Join We can get a parallel merge join plan using the same query hint as before, and adding trace flag 8649: SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (MERGE JOIN, QUERYTRACEON 8649); The execution plan is: This looks promising. It uses a similar strategy to distribute work across threads as seen for the parallel hash join. In practice though, performance is disappointing. On a typical run, the parallel merge plan runs for around 8400ms; slower than the single-threaded merge join plan (5000ms) and much worse than the 2600ms for the parallel hash join. We seem to be going backwards! The logical reads for the parallel merge are still exactly the same as before, with no physical IOs. The cardinality estimates and thread distribution are also still very good (click to enlarge): A big clue to the reason for the poor performance is shown in the wait statistics (captured by Plan Explorer Pro): CXPACKET waits require careful interpretation, and are most often benign, but in this case excessive waiting occurs at the repartitioning exchanges. Unlike the parallel hash join, the repartitioning exchanges in this plan are order-preserving ‘merging’ exchanges (because merge join requires ordered inputs): Parallelism works best when threads can just grab any available unit of work and get on with processing it. Preserving order introduces inter-thread dependencies that can easily lead to significant waits occurring. In extreme cases, these dependencies can result in an intra-query deadlock, though the details of that will have to wait for another time to explore in detail. The potential for waits and deadlocks leads the query optimizer to cost parallel merge join relatively highly, especially as the degree of parallelism (DOP) increases. This high costing resulted in the optimizer choosing a serial merge join rather than parallel in this case. The test results certainly confirm its reasoning. Collocated Joins In SQL Server 2008 and later, the optimizer has another available strategy when joining tables that share a common partition scheme. This strategy is a collocated join, also known as as a per-partition join. It can be applied in both serial and parallel execution plans, though it is limited to 2-way joins in the current optimizer. Whether the optimizer chooses a collocated join or not depends on cost estimation. The primary benefits of a collocated join are that it eliminates an exchange and requires less memory, as we will see next. Costing and Plan Selection The query optimizer did consider a collocated join for our original query, but it was rejected on cost grounds. The parallel hash join with repartitioning exchanges appeared to be a cheaper option. There is no query hint to force a collocated join, so we have to mess with the costing framework to produce one for our test query. Pretending that IOs cost 50 times more than usual is enough to convince the optimizer to use collocated join with our test query: -- Pretend IOs are 50x cost temporarily DBCC SETIOWEIGHT(50);   -- Co-located hash join SELECT COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID OPTION (RECOMPILE);   -- Reset IO costing DBCC SETIOWEIGHT(1); Collocated Join Plan The estimated execution plan for the collocated join is: The Constant Scan contains one row for each partition of the shared partitioning scheme, from 1 to 41. The hash repartitioning exchanges seen previously are replaced by a single Distribute Streams exchange using Demand partitioning. Demand partitioning means that the next partition id is given to the next parallel thread that asks for one. My test machine has eight logical processors, and all are available for SQL Server to use. As a result, there are eight threads in the single parallel branch in this plan, each processing one partition from each table at a time. Once a thread finishes processing a partition, it grabs a new partition number from the Distribute Streams exchange…and so on until all partitions have been processed. It is important to understand that the parallel scans in this plan are different from the parallel hash join plan. Although the scans have the same parallelism icon, tables T1 and T2 are not being co-operatively scanned by multiple threads in the same way. Each thread reads a single partition of T1 and performs a hash match join with the same partition from table T2. The properties of the two Clustered Index Scans show a Seek Predicate (unusual for a scan!) limiting the rows to a single partition: The crucial point is that the join between T1 and T2 is on TID, and TID is the partitioning column for both tables. A thread that processes partition ‘n’ is guaranteed to see all rows that can possibly join on TID for that partition. In addition, no other thread will see rows from that partition, so this removes the need for repartitioning exchanges. CPU and Memory Efficiency Improvements The collocated join has removed two expensive repartitioning exchanges and added a single exchange processing 41 rows (one for each partition id). Remember, the parallel hash join plan exchanges had to process 5 million and 15 million rows. The amount of processor time spent on exchanges will be much lower in the collocated join plan. In addition, the collocated join plan has a maximum of 8 threads processing single partitions at any one time. The 41 partitions will all be processed eventually, but a new partition is not started until a thread asks for it. Threads can reuse hash table memory for the new partition. The parallel hash join plan also had 8 hash tables, but with all 5,000,000 build rows loaded at the same time. The collocated plan needs memory for only 8 * 125,000 = 1,000,000 rows at any one time. Collocated Hash Join Performance The collated join plan has disappointing performance in this case. The query runs for around 25,300ms despite the same IO statistics as usual. This is much the worst result so far, so what went wrong? It turns out that cardinality estimation for the single partition scans of table T1 is slightly low. The properties of the Clustered Index Scan of T1 (graphic immediately above) show the estimation was for 121,951 rows. This is a small shortfall compared with the 125,000 rows actually encountered, but it was enough to cause the hash join to spill to physical tempdb: A level 1 spill doesn’t sound too bad, until you realize that the spill to tempdb probably occurs for each of the 41 partitions. As a side note, the cardinality estimation error is a little surprising because the system tables accurately show there are 125,000 rows in every partition of T1. Unfortunately, the optimizer uses regular column and index statistics to derive cardinality estimates here rather than system table information (e.g. sys.partitions). Collocated Merge Join We will never know how well the collocated parallel hash join plan might have worked without the cardinality estimation error (and the resulting 41 spills to tempdb) but we do know: Merge join does not require a memory grant; and Merge join was the optimizer’s preferred join option for a single partition join Putting this all together, what we would really like to see is the same collocated join strategy, but using merge join instead of hash join. Unfortunately, the current query optimizer cannot produce a collocated merge join; it only knows how to do collocated hash join. So where does this leave us? CROSS APPLY sys.partitions We can try to write our own collocated join query. We can use sys.partitions to find the partition numbers, and CROSS APPLY to get a count per partition, with a final step to sum the partial counts. The following query implements this idea: SELECT row_count = SUM(Subtotals.cnt) FROM ( -- Partition numbers SELECT p.partition_number FROM sys.partitions AS p WHERE p.[object_id] = OBJECT_ID(N'T1', N'U') AND p.index_id = 1 ) AS P CROSS APPLY ( -- Count per collocated join SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals; The estimated plan is: The cardinality estimates aren’t all that good here, especially the estimate for the scan of the system table underlying the sys.partitions view. Nevertheless, the plan shape is heading toward where we would like to be. Each partition number from the system table results in a per-partition scan of T1 and T2, a one-to-many Merge Join, and a Stream Aggregate to compute the partial counts. The final Stream Aggregate just sums the partial counts. Execution time for this query is around 3,500ms, with the same IO statistics as always. This compares favourably with 5,000ms for the serial plan produced by the optimizer with the OPTION (MERGE JOIN) hint. This is another case of the sum of the parts being less than the whole – summing 41 partial counts from 41 single-partition merge joins is faster than a single merge join and count over all partitions. Even so, this single-threaded collocated merge join is not as quick as the original parallel hash join plan, which executed in 2,600ms. On the positive side, our collocated merge join uses only one logical processor and requires no memory grant. The parallel hash join plan used 16 threads and reserved 569 MB of memory:   Using a Temporary Table Our collocated merge join plan should benefit from parallelism. The reason parallelism is not being used is that the query references a system table. We can work around that by writing the partition numbers to a temporary table (or table variable): SET STATISTICS IO ON; DECLARE @s datetime2 = SYSUTCDATETIME();   CREATE TABLE #P ( partition_number integer PRIMARY KEY);   INSERT #P (partition_number) SELECT p.partition_number FROM sys.partitions AS p WHERE p.[object_id] = OBJECT_ID(N'T1', N'U') AND p.index_id = 1;   SELECT row_count = SUM(Subtotals.cnt) FROM #P AS p CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals;   DROP TABLE #P;   SELECT DATEDIFF(Millisecond, @s, SYSUTCDATETIME()); SET STATISTICS IO OFF; Using the temporary table adds a few logical reads, but the overall execution time is still around 3500ms, indistinguishable from the same query without the temporary table. The problem is that the query optimizer still doesn’t choose a parallel plan for this query, though the removal of the system table reference means that it could if it chose to: In fact the optimizer did enter the parallel plan phase of query optimization (running search 1 for a second time): Unfortunately, the parallel plan found seemed to be more expensive than the serial plan. This is a crazy result, caused by the optimizer’s cost model not reducing operator CPU costs on the inner side of a nested loops join. Don’t get me started on that, we’ll be here all night. In this plan, everything expensive happens on the inner side of a nested loops join. Without a CPU cost reduction to compensate for the added cost of exchange operators, candidate parallel plans always look more expensive to the optimizer than the equivalent serial plan. Parallel Collocated Merge Join We can produce the desired parallel plan using trace flag 8649 again: SELECT row_count = SUM(Subtotals.cnt) FROM #P AS p CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals OPTION (QUERYTRACEON 8649); The actual execution plan is: One difference between this plan and the collocated hash join plan is that a Repartition Streams exchange operator is used instead of Distribute Streams. The effect is similar, though not quite identical. The Repartition uses round-robin partitioning, meaning the next partition id is pushed to the next thread in sequence. The Distribute Streams exchange seen earlier used Demand partitioning, meaning the next partition id is pulled across the exchange by the next thread that is ready for more work. There are subtle performance implications for each partitioning option, but going into that would again take us too far off the main point of this post. Performance The important thing is the performance of this parallel collocated merge join – just 1350ms on a typical run. The list below shows all the alternatives from this post (all timings include creation, population, and deletion of the temporary table where appropriate) from quickest to slowest: Collocated parallel merge join: 1350ms Parallel hash join: 2600ms Collocated serial merge join: 3500ms Serial merge join: 5000ms Parallel merge join: 8400ms Collated parallel hash join: 25,300ms (hash spill per partition) The parallel collocated merge join requires no memory grant (aside from a paltry 1.2MB used for exchange buffers). This plan uses 16 threads at DOP 8; but 8 of those are (rather pointlessly) allocated to the parallel scan of the temporary table. These are minor concerns, but it turns out there is a way to address them if it bothers you. Parallel Collocated Merge Join with Demand Partitioning This final tweak replaces the temporary table with a hard-coded list of partition ids (dynamic SQL could be used to generate this query from sys.partitions): SELECT row_count = SUM(Subtotals.cnt) FROM ( VALUES (1),(2),(3),(4),(5),(6),(7),(8),(9),(10), (11),(12),(13),(14),(15),(16),(17),(18),(19),(20), (21),(22),(23),(24),(25),(26),(27),(28),(29),(30), (31),(32),(33),(34),(35),(36),(37),(38),(39),(40),(41) ) AS P (partition_number) CROSS APPLY ( SELECT cnt = COUNT_BIG(*) FROM dbo.T1 AS T1 JOIN dbo.T2 AS T2 ON T2.TID = T1.TID WHERE $PARTITION.PFT(T1.TID) = p.partition_number AND $PARTITION.PFT(T2.TID) = p.partition_number ) AS SubTotals OPTION (QUERYTRACEON 8649); The actual execution plan is: The parallel collocated hash join plan is reproduced below for comparison: The manual rewrite has another advantage that has not been mentioned so far: the partial counts (per partition) can be computed earlier than the partial counts (per thread) in the optimizer’s collocated join plan. The earlier aggregation is performed by the extra Stream Aggregate under the nested loops join. The performance of the parallel collocated merge join is unchanged at around 1350ms. Final Words It is a shame that the current query optimizer does not consider a collocated merge join (Connect item closed as Won’t Fix). The example used in this post showed an improvement in execution time from 2600ms to 1350ms using a modestly-sized data set and limited parallelism. In addition, the memory requirement for the query was almost completely eliminated  – down from 569MB to 1.2MB. The problem with the parallel hash join selected by the optimizer is that it attempts to process the full data set all at once (albeit using eight threads). It requires a large memory grant to hold all 5 million rows from table T1 across the eight hash tables, and does not take advantage of the divide-and-conquer opportunity offered by the common partitioning. The great thing about the collocated join strategies is that each parallel thread works on a single partition from both tables, reading rows, performing the join, and computing a per-partition subtotal, before moving on to a new partition. From a thread’s point of view… If you have trouble visualizing what is happening from just looking at the parallel collocated merge join execution plan, let’s look at it again, but from the point of view of just one thread operating between the two Parallelism (exchange) operators. Our thread picks up a single partition id from the Distribute Streams exchange, and starts a merge join using ordered rows from partition 1 of table T1 and partition 1 of table T2. By definition, this is all happening on a single thread. As rows join, they are added to a (per-partition) count in the Stream Aggregate immediately above the Merge Join. Eventually, either T1 (partition 1) or T2 (partition 1) runs out of rows and the merge join stops. The per-partition count from the aggregate passes on through the Nested Loops join to another Stream Aggregate, which is maintaining a per-thread subtotal. Our same thread now picks up a new partition id from the exchange (say it gets id 9 this time). The count in the per-partition aggregate is reset to zero, and the processing of partition 9 of both tables proceeds just as it did for partition 1, and on the same thread. Each thread picks up a single partition id and processes all the data for that partition, completely independently from other threads working on other partitions. One thread might eventually process partitions (1, 9, 17, 25, 33, 41) while another is concurrently processing partitions (2, 10, 18, 26, 34) and so on for the other six threads at DOP 8. The point is that all 8 threads can execute independently and concurrently, continuing to process new partitions until the wider job (of which the thread has no knowledge!) is done. This divide-and-conquer technique can be much more efficient than simply splitting the entire workload across eight threads all at once. Related Reading Understanding and Using Parallelism in SQL Server Parallel Execution Plans Suck © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

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  • Toorcon 15 (2013)

    - by danx
    The Toorcon gang (senior staff): h1kari (founder), nfiltr8, and Geo Introduction to Toorcon 15 (2013) A Tale of One Software Bypass of MS Windows 8 Secure Boot Breaching SSL, One Byte at a Time Running at 99%: Surviving an Application DoS Security Response in the Age of Mass Customized Attacks x86 Rewriting: Defeating RoP and other Shinanighans Clowntown Express: interesting bugs and running a bug bounty program Active Fingerprinting of Encrypted VPNs Making Attacks Go Backwards Mask Your Checksums—The Gorry Details Adventures with weird machines thirty years after "Reflections on Trusting Trust" Introduction to Toorcon 15 (2013) Toorcon 15 is the 15th annual security conference held in San Diego. I've attended about a third of them and blogged about previous conferences I attended here starting in 2003. As always, I've only summarized the talks I attended and interested me enough to write about them. Be aware that I may have misrepresented the speaker's remarks and that they are not my remarks or opinion, or those of my employer, so don't quote me or them. Those seeking further details may contact the speakers directly or use The Google. For some talks, I have a URL for further information. A Tale of One Software Bypass of MS Windows 8 Secure Boot Andrew Furtak and Oleksandr Bazhaniuk Yuri Bulygin, Oleksandr ("Alex") Bazhaniuk, and (not present) Andrew Furtak Yuri and Alex talked about UEFI and Bootkits and bypassing MS Windows 8 Secure Boot, with vendor recommendations. They previously gave this talk at the BlackHat 2013 conference. MS Windows 8 Secure Boot Overview UEFI (Unified Extensible Firmware Interface) is interface between hardware and OS. UEFI is processor and architecture independent. Malware can replace bootloader (bootx64.efi, bootmgfw.efi). Once replaced can modify kernel. Trivial to replace bootloader. Today many legacy bootkits—UEFI replaces them most of them. MS Windows 8 Secure Boot verifies everything you load, either through signatures or hashes. UEFI firmware relies on secure update (with signed update). You would think Secure Boot would rely on ROM (such as used for phones0, but you can't do that for PCs—PCs use writable memory with signatures DXE core verifies the UEFI boat loader(s) OS Loader (winload.efi, winresume.efi) verifies the OS kernel A chain of trust is established with a root key (Platform Key, PK), which is a cert belonging to the platform vendor. Key Exchange Keys (KEKs) verify an "authorized" database (db), and "forbidden" database (dbx). X.509 certs with SHA-1/SHA-256 hashes. Keys are stored in non-volatile (NV) flash-based NVRAM. Boot Services (BS) allow adding/deleting keys (can't be accessed once OS starts—which uses Run-Time (RT)). Root cert uses RSA-2048 public keys and PKCS#7 format signatures. SecureBoot — enable disable image signature checks SetupMode — update keys, self-signed keys, and secure boot variables CustomMode — allows updating keys Secure Boot policy settings are: always execute, never execute, allow execute on security violation, defer execute on security violation, deny execute on security violation, query user on security violation Attacking MS Windows 8 Secure Boot Secure Boot does NOT protect from physical access. Can disable from console. Each BIOS vendor implements Secure Boot differently. There are several platform and BIOS vendors. It becomes a "zoo" of implementations—which can be taken advantage of. Secure Boot is secure only when all vendors implement it correctly. Allow only UEFI firmware signed updates protect UEFI firmware from direct modification in flash memory protect FW update components program SPI controller securely protect secure boot policy settings in nvram protect runtime api disable compatibility support module which allows unsigned legacy Can corrupt the Platform Key (PK) EFI root certificate variable in SPI flash. If PK is not found, FW enters setup mode wich secure boot turned off. Can also exploit TPM in a similar manner. One is not supposed to be able to directly modify the PK in SPI flash from the OS though. But they found a bug that they can exploit from User Mode (undisclosed) and demoed the exploit. It loaded and ran their own bootkit. The exploit requires a reboot. Multiple vendors are vulnerable. They will disclose this exploit to vendors in the future. Recommendations: allow only signed updates protect UEFI fw in ROM protect EFI variable store in ROM Breaching SSL, One Byte at a Time Yoel Gluck and Angelo Prado Angelo Prado and Yoel Gluck, Salesforce.com CRIME is software that performs a "compression oracle attack." This is possible because the SSL protocol doesn't hide length, and because SSL compresses the header. CRIME requests with every possible character and measures the ciphertext length. Look for the plaintext which compresses the most and looks for the cookie one byte-at-a-time. SSL Compression uses LZ77 to reduce redundancy. Huffman coding replaces common byte sequences with shorter codes. US CERT thinks the SSL compression problem is fixed, but it isn't. They convinced CERT that it wasn't fixed and they issued a CVE. BREACH, breachattrack.com BREACH exploits the SSL response body (Accept-Encoding response, Content-Encoding). It takes advantage of the fact that the response is not compressed. BREACH uses gzip and needs fairly "stable" pages that are static for ~30 seconds. It needs attacker-supplied content (say from a web form or added to a URL parameter). BREACH listens to a session's requests and responses, then inserts extra requests and responses. Eventually, BREACH guesses a session's secret key. Can use compression to guess contents one byte at-a-time. For example, "Supersecret SupersecreX" (a wrong guess) compresses 10 bytes, and "Supersecret Supersecret" (a correct guess) compresses 11 bytes, so it can find each character by guessing every character. To start the guess, BREACH needs at least three known initial characters in the response sequence. Compression length then "leaks" information. Some roadblocks include no winners (all guesses wrong) or too many winners (multiple possibilities that compress the same). The solutions include: lookahead (guess 2 or 3 characters at-a-time instead of 1 character). Expensive rollback to last known conflict check compression ratio can brute-force first 3 "bootstrap" characters, if needed (expensive) block ciphers hide exact plain text length. Solution is to align response in advance to block size Mitigations length: use variable padding secrets: dynamic CSRF tokens per request secret: change over time separate secret to input-less servlets Future work eiter understand DEFLATE/GZIP HTTPS extensions Running at 99%: Surviving an Application DoS Ryan Huber Ryan Huber, Risk I/O Ryan first discussed various ways to do a denial of service (DoS) attack against web services. One usual method is to find a slow web page and do several wgets. Or download large files. Apache is not well suited at handling a large number of connections, but one can put something in front of it Can use Apache alternatives, such as nginx How to identify malicious hosts short, sudden web requests user-agent is obvious (curl, python) same url requested repeatedly no web page referer (not normal) hidden links. hide a link and see if a bot gets it restricted access if not your geo IP (unless the website is global) missing common headers in request regular timing first seen IP at beginning of attack count requests per hosts (usually a very large number) Use of captcha can mitigate attacks, but you'll lose a lot of genuine users. Bouncer, goo.gl/c2vyEc and www.github.com/rawdigits/Bouncer Bouncer is software written by Ryan in netflow. Bouncer has a small, unobtrusive footprint and detects DoS attempts. It closes blacklisted sockets immediately (not nice about it, no proper close connection). Aggregator collects requests and controls your web proxies. Need NTP on the front end web servers for clean data for use by bouncer. Bouncer is also useful for a popularity storm ("Slashdotting") and scraper storms. Future features: gzip collection data, documentation, consumer library, multitask, logging destroyed connections. Takeaways: DoS mitigation is easier with a complete picture Bouncer designed to make it easier to detect and defend DoS—not a complete cure Security Response in the Age of Mass Customized Attacks Peleus Uhley and Karthik Raman Peleus Uhley and Karthik Raman, Adobe ASSET, blogs.adobe.com/asset/ Peleus and Karthik talked about response to mass-customized exploits. Attackers behave much like a business. "Mass customization" refers to concept discussed in the book Future Perfect by Stan Davis of Harvard Business School. Mass customization is differentiating a product for an individual customer, but at a mass production price. For example, the same individual with a debit card receives basically the same customized ATM experience around the world. Or designing your own PC from commodity parts. Exploit kits are another example of mass customization. The kits support multiple browsers and plugins, allows new modules. Exploit kits are cheap and customizable. Organized gangs use exploit kits. A group at Berkeley looked at 77,000 malicious websites (Grier et al., "Manufacturing Compromise: The Emergence of Exploit-as-a-Service", 2012). They found 10,000 distinct binaries among them, but derived from only a dozen or so exploit kits. Characteristics of Mass Malware: potent, resilient, relatively low cost Technical characteristics: multiple OS, multipe payloads, multiple scenarios, multiple languages, obfuscation Response time for 0-day exploits has gone down from ~40 days 5 years ago to about ~10 days now. So the drive with malware is towards mass customized exploits, to avoid detection There's plenty of evicence that exploit development has Project Manager bureaucracy. They infer from the malware edicts to: support all versions of reader support all versions of windows support all versions of flash support all browsers write large complex, difficult to main code (8750 lines of JavaScript for example Exploits have "loose coupling" of multipe versions of software (adobe), OS, and browser. This allows specific attacks against specific versions of multiple pieces of software. Also allows exploits of more obscure software/OS/browsers and obscure versions. Gave examples of exploits that exploited 2, 3, 6, or 14 separate bugs. However, these complete exploits are more likely to be buggy or fragile in themselves and easier to defeat. Future research includes normalizing malware and Javascript. Conclusion: The coming trend is that mass-malware with mass zero-day attacks will result in mass customization of attacks. x86 Rewriting: Defeating RoP and other Shinanighans Richard Wartell Richard Wartell The attack vector we are addressing here is: First some malware causes a buffer overflow. The malware has no program access, but input access and buffer overflow code onto stack Later the stack became non-executable. The workaround malware used was to write a bogus return address to the stack jumping to malware Later came ASLR (Address Space Layout Randomization) to randomize memory layout and make addresses non-deterministic. The workaround malware used was to jump t existing code segments in the program that can be used in bad ways "RoP" is Return-oriented Programming attacks. RoP attacks use your own code and write return address on stack to (existing) expoitable code found in program ("gadgets"). Pinkie Pie was paid $60K last year for a RoP attack. One solution is using anti-RoP compilers that compile source code with NO return instructions. ASLR does not randomize address space, just "gadgets". IPR/ILR ("Instruction Location Randomization") randomizes each instruction with a virtual machine. Richard's goal was to randomize a binary with no source code access. He created "STIR" (Self-Transofrming Instruction Relocation). STIR disassembles binary and operates on "basic blocks" of code. The STIR disassembler is conservative in what to disassemble. Each basic block is moved to a random location in memory. Next, STIR writes new code sections with copies of "basic blocks" of code in randomized locations. The old code is copied and rewritten with jumps to new code. the original code sections in the file is marked non-executible. STIR has better entropy than ASLR in location of code. Makes brute force attacks much harder. STIR runs on MS Windows (PEM) and Linux (ELF). It eliminated 99.96% or more "gadgets" (i.e., moved the address). Overhead usually 5-10% on MS Windows, about 1.5-4% on Linux (but some code actually runs faster!). The unique thing about STIR is it requires no source access and the modified binary fully works! Current work is to rewrite code to enforce security policies. For example, don't create a *.{exe,msi,bat} file. Or don't connect to the network after reading from the disk. Clowntown Express: interesting bugs and running a bug bounty program Collin Greene Collin Greene, Facebook Collin talked about Facebook's bug bounty program. Background at FB: FB has good security frameworks, such as security teams, external audits, and cc'ing on diffs. But there's lots of "deep, dark, forgotten" parts of legacy FB code. Collin gave several examples of bountied bugs. Some bounty submissions were on software purchased from a third-party (but bounty claimers don't know and don't care). We use security questions, as does everyone else, but they are basically insecure (often easily discoverable). Collin didn't expect many bugs from the bounty program, but they ended getting 20+ good bugs in first 24 hours and good submissions continue to come in. Bug bounties bring people in with different perspectives, and are paid only for success. Bug bounty is a better use of a fixed amount of time and money versus just code review or static code analysis. The Bounty program started July 2011 and paid out $1.5 million to date. 14% of the submissions have been high priority problems that needed to be fixed immediately. The best bugs come from a small % of submitters (as with everything else)—the top paid submitters are paid 6 figures a year. Spammers like to backstab competitors. The youngest sumitter was 13. Some submitters have been hired. Bug bounties also allows to see bugs that were missed by tools or reviews, allowing improvement in the process. Bug bounties might not work for traditional software companies where the product has release cycle or is not on Internet. Active Fingerprinting of Encrypted VPNs Anna Shubina Anna Shubina, Dartmouth Institute for Security, Technology, and Society (I missed the start of her talk because another track went overtime. But I have the DVD of the talk, so I'll expand later) IPsec leaves fingerprints. Using netcat, one can easily visually distinguish various crypto chaining modes just from packet timing on a chart (example, DES-CBC versus AES-CBC) One can tell a lot about VPNs just from ping roundtrips (such as what router is used) Delayed packets are not informative about a network, especially if far away from the network More needed to explore about how TCP works in real life with respect to timing Making Attacks Go Backwards Fuzzynop FuzzyNop, Mandiant This talk is not about threat attribution (finding who), product solutions, politics, or sales pitches. But who are making these malware threats? It's not a single person or group—they have diverse skill levels. There's a lot of fat-fingered fumblers out there. Always look for low-hanging fruit first: "hiding" malware in the temp, recycle, or root directories creation of unnamed scheduled tasks obvious names of files and syscalls ("ClearEventLog") uncleared event logs. Clearing event log in itself, and time of clearing, is a red flag and good first clue to look for on a suspect system Reverse engineering is hard. Disassembler use takes practice and skill. A popular tool is IDA Pro, but it takes multiple interactive iterations to get a clean disassembly. Key loggers are used a lot in targeted attacks. They are typically custom code or built in a backdoor. A big tip-off is that non-printable characters need to be printed out (such as "[Ctrl]" "[RightShift]") or time stamp printf strings. Look for these in files. Presence is not proof they are used. Absence is not proof they are not used. Java exploits. Can parse jar file with idxparser.py and decomile Java file. Java typially used to target tech companies. Backdoors are the main persistence mechanism (provided externally) for malware. Also malware typically needs command and control. Application of Artificial Intelligence in Ad-Hoc Static Code Analysis John Ashaman John Ashaman, Security Innovation Initially John tried to analyze open source files with open source static analysis tools, but these showed thousands of false positives. Also tried using grep, but tis fails to find anything even mildly complex. So next John decided to write his own tool. His approach was to first generate a call graph then analyze the graph. However, the problem is that making a call graph is really hard. For example, one problem is "evil" coding techniques, such as passing function pointer. First the tool generated an Abstract Syntax Tree (AST) with the nodes created from method declarations and edges created from method use. Then the tool generated a control flow graph with the goal to find a path through the AST (a maze) from source to sink. The algorithm is to look at adjacent nodes to see if any are "scary" (a vulnerability), using heuristics for search order. The tool, called "Scat" (Static Code Analysis Tool), currently looks for C# vulnerabilities and some simple PHP. Later, he plans to add more PHP, then JSP and Java. For more information see his posts in Security Innovation blog and NRefactory on GitHub. Mask Your Checksums—The Gorry Details Eric (XlogicX) Davisson Eric (XlogicX) Davisson Sometimes in emailing or posting TCP/IP packets to analyze problems, you may want to mask the IP address. But to do this correctly, you need to mask the checksum too, or you'll leak information about the IP. Problem reports found in stackoverflow.com, sans.org, and pastebin.org are usually not masked, but a few companies do care. If only the IP is masked, the IP may be guessed from checksum (that is, it leaks data). Other parts of packet may leak more data about the IP. TCP and IP checksums both refer to the same data, so can get more bits of information out of using both checksums than just using one checksum. Also, one can usually determine the OS from the TTL field and ports in a packet header. If we get hundreds of possible results (16x each masked nibble that is unknown), one can do other things to narrow the results, such as look at packet contents for domain or geo information. With hundreds of results, can import as CSV format into a spreadsheet. Can corelate with geo data and see where each possibility is located. Eric then demoed a real email report with a masked IP packet attached. Was able to find the exact IP address, given the geo and university of the sender. Point is if you're going to mask a packet, do it right. Eric wouldn't usually bother, but do it correctly if at all, to not create a false impression of security. Adventures with weird machines thirty years after "Reflections on Trusting Trust" Sergey Bratus Sergey Bratus, Dartmouth College (and Julian Bangert and Rebecca Shapiro, not present) "Reflections on Trusting Trust" refers to Ken Thompson's classic 1984 paper. "You can't trust code that you did not totally create yourself." There's invisible links in the chain-of-trust, such as "well-installed microcode bugs" or in the compiler, and other planted bugs. Thompson showed how a compiler can introduce and propagate bugs in unmodified source. But suppose if there's no bugs and you trust the author, can you trust the code? Hell No! There's too many factors—it's Babylonian in nature. Why not? Well, Input is not well-defined/recognized (code's assumptions about "checked" input will be violated (bug/vunerabiliy). For example, HTML is recursive, but Regex checking is not recursive. Input well-formed but so complex there's no telling what it does For example, ELF file parsing is complex and has multiple ways of parsing. Input is seen differently by different pieces of program or toolchain Any Input is a program input executes on input handlers (drives state changes & transitions) only a well-defined execution model can be trusted (regex/DFA, PDA, CFG) Input handler either is a "recognizer" for the inputs as a well-defined language (see langsec.org) or it's a "virtual machine" for inputs to drive into pwn-age ELF ABI (UNIX/Linux executible file format) case study. Problems can arise from these steps (without planting bugs): compiler linker loader ld.so/rtld relocator DWARF (debugger info) exceptions The problem is you can't really automatically analyze code (it's the "halting problem" and undecidable). Only solution is to freeze code and sign it. But you can't freeze everything! Can't freeze ASLR or loading—must have tables and metadata. Any sufficiently complex input data is the same as VM byte code Example, ELF relocation entries + dynamic symbols == a Turing Complete Machine (TM). @bxsays created a Turing machine in Linux from relocation data (not code) in an ELF file. For more information, see Rebecca "bx" Shapiro's presentation from last year's Toorcon, "Programming Weird Machines with ELF Metadata" @bxsays did same thing with Mach-O bytecode Or a DWARF exception handling data .eh_frame + glibc == Turning Machine X86 MMU (IDT, GDT, TSS): used address translation to create a Turning Machine. Page handler reads and writes (on page fault) memory. Uses a page table, which can be used as Turning Machine byte code. Example on Github using this TM that will fly a glider across the screen Next Sergey talked about "Parser Differentials". That having one input format, but two parsers, will create confusion and opportunity for exploitation. For example, CSRs are parsed during creation by cert requestor and again by another parser at the CA. Another example is ELF—several parsers in OS tool chain, which are all different. Can have two different Program Headers (PHDRs) because ld.so parses multiple PHDRs. The second PHDR can completely transform the executable. This is described in paper in the first issue of International Journal of PoC. Conclusions trusting computers not only about bugs! Bugs are part of a problem, but no by far all of it complex data formats means bugs no "chain of trust" in Babylon! (that is, with parser differentials) we need to squeeze complexity out of data until data stops being "code equivalent" Further information See and langsec.org. USENIX WOOT 2013 (Workshop on Offensive Technologies) for "weird machines" papers and videos.

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  • Quick guide to Oracle IRM 11g: Classification design

    - by Simon Thorpe
    Quick guide to Oracle IRM 11g indexThis is the final article in the quick guide to Oracle IRM. If you've followed everything prior you will now have a fully functional and tested Information Rights Management service. It doesn't matter if you've been following the 10g or 11g guide as this next article is common to both. ContentsWhy this is the most important part... Understanding the classification and standard rights model Identifying business use cases Creating an effective IRM classification modelOne single classification across the entire businessA context for each and every possible granular use caseWhat makes a good context? Deciding on the use of roles in the context Reviewing the features and security for context roles Summary Why this is the most important part...Now the real work begins, installing and getting an IRM system running is as simple as following instructions. However to actually have an IRM technology easily protecting your most sensitive information without interfering with your users existing daily work flows and be able to scale IRM across the entire business, requires thought into how confidential documents are created, used and distributed. This article is going to give you the information you need to ask the business the right questions so that you can deploy your IRM service successfully. The IRM team here at Oracle have over 10 years of experience in helping customers and it is important you understand the following to be successful in securing access to your most confidential information. Whatever you are trying to secure, be it mergers and acquisitions information, engineering intellectual property, health care documentation or financial reports. No matter what type of user is going to access the information, be they employees, contractors or customers, there are common goals you are always trying to achieve.Securing the content at the earliest point possible and do it automatically. Removing the dependency on the user to decide to secure the content reduces the risk of mistakes significantly and therefore results a more secure deployment. K.I.S.S. (Keep It Simple Stupid) Reduce complexity in the rights/classification model. Oracle IRM lets you make changes to access to documents even after they are secured which allows you to start with a simple model and then introduce complexity once you've understood how the technology is going to be used in the business. After an initial learning period you can review your implementation and start to make informed decisions based on user feedback and administration experience. Clearly communicate to the user, when appropriate, any changes to their existing work practice. You must make every effort to make the transition to sealed content as simple as possible. For external users you must help them understand why you are securing the documents and inform them the value of the technology to both your business and them. Before getting into the detail, I must pay homage to Martin White, Vice President of client services in SealedMedia, the company Oracle acquired and who created Oracle IRM. In the SealedMedia years Martin was involved with every single customer and was key to the design of certain aspects of the IRM technology, specifically the context model we will be discussing here. Listening carefully to customers and understanding the flexibility of the IRM technology, Martin taught me all the skills of helping customers build scalable, effective and simple to use IRM deployments. No matter how well the engineering department designed the software, badly designed and poorly executed projects can result in difficult to use and manage, and ultimately insecure solutions. The advice and information that follows was born with Martin and he's still delivering IRM consulting with customers and can be found at www.thinkers.co.uk. It is from Martin and others that Oracle not only has the most advanced, scalable and usable document security solution on the market, but Oracle and their partners have the most experience in delivering successful document security solutions. Understanding the classification and standard rights model The goal of any successful IRM deployment is to balance the increase in security the technology brings without over complicating the way people use secured content and avoid a significant increase in administration and maintenance. With Oracle it is possible to automate the protection of content, deploy the desktop software transparently and use authentication methods such that users can open newly secured content initially unaware the document is any different to an insecure one. That is until of course they attempt to do something for which they don't have any rights, such as copy and paste to an insecure application or try and print. Central to achieving this objective is creating a classification model that is simple to understand and use but also provides the right level of complexity to meet the business needs. In Oracle IRM the term used for each classification is a "context". A context defines the relationship between.A group of related documents The people that use the documents The roles that these people perform The rights that these people need to perform their role The context is the key to the success of Oracle IRM. It provides the separation of the role and rights of a user from the content itself. Documents are sealed to contexts but none of the rights, user or group information is stored within the content itself. Sealing only places information about the location of the IRM server that sealed it, the context applied to the document and a few other pieces of metadata that pertain only to the document. This important separation of rights from content means that millions of documents can be secured against a single classification and a user needs only one right assigned to be able to access all documents. If you have followed all the previous articles in this guide, you will be ready to start defining contexts to which your sensitive information will be protected. But before you even start with IRM, you need to understand how your own business uses and creates sensitive documents and emails. Identifying business use cases Oracle is able to support multiple classification systems, but usually there is one single initial need for the technology which drives a deployment. This need might be to protect sensitive mergers and acquisitions information, engineering intellectual property, financial documents. For this and every subsequent use case you must understand how users create and work with documents, to who they are distributed and how the recipients should interact with them. A successful IRM deployment should start with one well identified use case (we go through some examples towards the end of this article) and then after letting this use case play out in the business, you learn how your users work with content, how well your communication to the business worked and if the classification system you deployed delivered the right balance. It is at this point you can start rolling the technology out further. Creating an effective IRM classification model Once you have selected the initial use case you will address with IRM, you need to design a classification model that defines the access to secured documents within the use case. In Oracle IRM there is an inbuilt classification system called the "context" model. In Oracle IRM 11g it is possible to extend the server to support any rights classification model, but the majority of users who are not using an application integration (such as Oracle IRM within Oracle Beehive) are likely to be starting out with the built in context model. Before looking at creating a classification system with IRM, it is worth reviewing some recognized standards and methods for creating and implementing security policy. A very useful set of documents are the ISO 17799 guidelines and the SANS security policy templates. First task is to create a context against which documents are to be secured. A context consists of a group of related documents (all top secret engineering research), a list of roles (contributors and readers) which define how users can access documents and a list of users (research engineers) who have been given a role allowing them to interact with sealed content. Before even creating the first context it is wise to decide on a philosophy which will dictate the level of granularity, the question is, where do you start? At a department level? By project? By technology? First consider the two ends of the spectrum... One single classification across the entire business Imagine that instead of having separate contexts, one for engineering intellectual property, one for your financial data, one for human resources personally identifiable information, you create one context for all documents across the entire business. Whilst you may have immediate objections, there are some significant benefits in thinking about considering this. Document security classification decisions are simple. You only have one context to chose from! User provisioning is simple, just make sure everyone has a role in the only context in the business. Administration is very low, if you assign rights to groups from the business user repository you probably never have to touch IRM administration again. There are however some obvious downsides to this model.All users in have access to all IRM secured content. So potentially a sales person could access sensitive mergers and acquisition documents, if they can get their hands on a copy that is. You cannot delegate control of different documents to different parts of the business, this may not satisfy your regulatory requirements for the separation and delegation of duties. Changing a users role affects every single document ever secured. Even though it is very unlikely a business would ever use one single context to secure all their sensitive information, thinking about this scenario raises one very important point. Just having one single context and securing all confidential documents to it, whilst incurring some of the problems detailed above, has one huge value. Once secured, IRM protected content can ONLY be accessed by authorized users. Just think of all the sensitive documents in your business today, imagine if you could ensure that only everyone you trust could open them. Even if an employee lost a laptop or someone accidentally sent an email to the wrong recipient, only the right people could open that file. A context for each and every possible granular use case Now let's think about the total opposite of a single context design. What if you created a context for each and every single defined business need and created multiple contexts within this for each level of granularity? Let's take a use case where we need to protect engineering intellectual property. Imagine we have 6 different engineering groups, and in each we have a research department, a design department and manufacturing. The company information security policy defines 3 levels of information sensitivity... restricted, confidential and top secret. Then let's say that each group and department needs to define access to information from both internal and external users. Finally add into the mix that they want to review the rights model for each context every financial quarter. This would result in a huge amount of contexts. For example, lets just look at the resulting contexts for one engineering group. Q1FY2010 Restricted Internal - Engineering Group 1 - Research Q1FY2010 Restricted Internal - Engineering Group 1 - Design Q1FY2010 Restricted Internal - Engineering Group 1 - Manufacturing Q1FY2010 Restricted External- Engineering Group 1 - Research Q1FY2010 Restricted External - Engineering Group 1 - Design Q1FY2010 Restricted External - Engineering Group 1 - Manufacturing Q1FY2010 Confidential Internal - Engineering Group 1 - Research Q1FY2010 Confidential Internal - Engineering Group 1 - Design Q1FY2010 Confidential Internal - Engineering Group 1 - Manufacturing Q1FY2010 Confidential External - Engineering Group 1 - Research Q1FY2010 Confidential External - Engineering Group 1 - Design Q1FY2010 Confidential External - Engineering Group 1 - Manufacturing Q1FY2010 Top Secret Internal - Engineering Group 1 - Research Q1FY2010 Top Secret Internal - Engineering Group 1 - Design Q1FY2010 Top Secret Internal - Engineering Group 1 - Manufacturing Q1FY2010 Top Secret External - Engineering Group 1 - Research Q1FY2010 Top Secret External - Engineering Group 1 - Design Q1FY2010 Top Secret External - Engineering Group 1 - Manufacturing Now multiply the above by 6 for each engineering group, 18 contexts. You are then creating/reviewing another 18 every 3 months. After a year you've got 72 contexts. What would be the advantages of such a complex classification model? You can satisfy very granular rights requirements, for example only an authorized engineering group 1 researcher can create a top secret report for access internally, and his role will be reviewed on a very frequent basis. Your business may have very complex rights requirements and mapping this directly to IRM may be an obvious exercise. The disadvantages of such a classification model are significant...Huge administrative overhead. Someone in the business must manage, review and administrate each of these contexts. If the engineering group had a single administrator, they would have 72 classifications to reside over each year. From an end users perspective life will be very confusing. Imagine if a user has rights in just 6 of these contexts. They may be able to print content from one but not another, be able to edit content in 2 contexts but not the other 4. Such confusion at the end user level causes frustration and resistance to the use of the technology. Increased synchronization complexity. Imagine a user who after 3 years in the company ends up with over 300 rights in many different contexts across the business. This would result in long synchronization times as the client software updates all your offline rights. Hard to understand who can do what with what. Imagine being the VP of engineering and as part of an internal security audit you are asked the question, "What rights to researchers have to our top secret information?". In this complex model the answer is not simple, it would depend on many roles in many contexts. Of course this example is extreme, but it highlights that trying to build many barriers in your business can result in a nightmare of administration and confusion amongst users. In the real world what we need is a balance of the two. We need to seek an optimum number of contexts. Too many contexts are unmanageable and too few contexts does not give fine enough granularity. What makes a good context? Good context design derives mainly from how well you understand your business requirements to secure access to confidential information. Some customers I have worked with can tell me exactly the documents they wish to secure and know exactly who should be opening them. However there are some customers who know only of the government regulation that requires them to control access to certain types of information, they don't actually know where the documents are, how they are created or understand exactly who should have access. Therefore you need to know how to ask the business the right questions that lead to information which help you define a context. First ask these questions about a set of documentsWhat is the topic? Who are legitimate contributors on this topic? Who are the authorized readership? If the answer to any one of these is significantly different, then it probably merits a separate context. Remember that sealed documents are inherently secure and as such they cannot leak to your competitors, therefore it is better sealed to a broad context than not sealed at all. Simplicity is key here. Always revert to the first extreme example of a single classification, then work towards essential complexity. If there is any doubt, always prefer fewer contexts. Remember, Oracle IRM allows you to change your mind later on. You can implement a design now and continue to change and refine as you learn how the technology is used. It is easy to go from a simple model to a more complex one, it is much harder to take a complex model that is already embedded in the work practice of users and try to simplify it. It is also wise to take a single use case and address this first with the business. Don't try and tackle many different problems from the outset. Do one, learn from the process, refine it and then take what you have learned into the next use case, refine and continue. Once you have a good grasp of the technology and understand how your business will use it, you can then start rolling out the technology wider across the business. Deciding on the use of roles in the context Once you have decided on that first initial use case and a context to create let's look at the details you need to decide upon. For each context, identify; Administrative rolesBusiness owner, the person who makes decisions about who may or may not see content in this context. This is often the person who wanted to use IRM and drove the business purchase. They are the usually the person with the most at risk when sensitive information is lost. Point of contact, the person who will handle requests for access to content. Sometimes the same as the business owner, sometimes a trusted secretary or administrator. Context administrator, the person who will enact the decisions of the Business Owner. Sometimes the point of contact, sometimes a trusted IT person. Document related rolesContributors, the people who create and edit documents in this context. Reviewers, the people who are involved in reviewing documents but are not trusted to secure information to this classification. This role is not always necessary. (See later discussion on Published-work and Work-in-Progress) Readers, the people who read documents from this context. Some people may have several of the roles above, which is fine. What you are trying to do is understand and define how the business interacts with your sensitive information. These roles obviously map directly to roles available in Oracle IRM. Reviewing the features and security for context roles At this point we have decided on a classification of information, understand what roles people in the business will play when administrating this classification and how they will interact with content. The final piece of the puzzle in getting the information for our first context is to look at the permissions people will have to sealed documents. First think why are you protecting the documents in the first place? It is to prevent the loss of leaking of information to the wrong people. To control the information, making sure that people only access the latest versions of documents. You are not using Oracle IRM to prevent unauthorized people from doing legitimate work. This is an important point, with IRM you can erect many barriers to prevent access to content yet too many restrictions and authorized users will often find ways to circumvent using the technology and end up distributing unprotected originals. Because IRM is a security technology, it is easy to get carried away restricting different groups. However I would highly recommend starting with a simple solution with few restrictions. Ensure that everyone who reasonably needs to read documents can do so from the outset. Remember that with Oracle IRM you can change rights to content whenever you wish and tighten security. Always return to the fact that the greatest value IRM brings is that ONLY authorized users can access secured content, remember that simple "one context for the entire business" model. At the start of the deployment you really need to aim for user acceptance and therefore a simple model is more likely to succeed. As time passes and users understand how IRM works you can start to introduce more restrictions and complexity. Another key aspect to focus on is handling exceptions. If you decide on a context model where engineering can only access engineering information, and sales can only access sales data. Act quickly when a sales manager needs legitimate access to a set of engineering documents. Having a quick and effective process for permitting other people with legitimate needs to obtain appropriate access will be rewarded with acceptance from the user community. These use cases can often be satisfied by integrating IRM with a good Identity & Access Management technology which simplifies the process of assigning users the correct business roles. The big print issue... Printing is often an issue of contention, users love to print but the business wants to ensure sensitive information remains in the controlled digital world. There are many cases of physical document loss causing a business pain, it is often overlooked that IRM can help with this issue by limiting the ability to generate physical copies of digital content. However it can be hard to maintain a balance between security and usability when it comes to printing. Consider the following points when deciding about whether to give print rights. Oracle IRM sealed documents can contain watermarks that expose information about the user, time and location of access and the classification of the document. This information would reside in the printed copy making it easier to trace who printed it. Printed documents are slower to distribute in comparison to their digital counterparts, so time sensitive information in printed format may present a lower risk. Print activity is audited, therefore you can monitor and react to users abusing print rights. Summary In summary it is important to think carefully about the way you create your context model. As you ask the business these questions you may get a variety of different requirements. There may be special projects that require a context just for sensitive information created during the lifetime of the project. There may be a department that requires all information in the group is secured and you might have a few senior executives who wish to use IRM to exchange a small number of highly sensitive documents with a very small number of people. Oracle IRM, with its very flexible context classification system, can support all of these use cases. The trick is to introducing the complexity to deliver them at the right level. In another article i'm working on I will go through some examples of how Oracle IRM might map to existing business use cases. But for now, this article covers all the important questions you need to get your IRM service deployed and successfully protecting your most sensitive information.

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  • How to find and fix performance problems in ORM powered applications

    - by FransBouma
    Once in a while we get requests about how to fix performance problems with our framework. As it comes down to following the same steps and looking into the same things every single time, I decided to write a blogpost about it instead, so more people can learn from this and solve performance problems in their O/R mapper powered applications. In some parts it's focused on LLBLGen Pro but it's also usable for other O/R mapping frameworks, as the vast majority of performance problems in O/R mapper powered applications are not specific for a certain O/R mapper framework. Too often, the developer looks at the wrong part of the application, trying to fix what isn't a problem in that part, and getting frustrated that 'things are so slow with <insert your favorite framework X here>'. I'm in the O/R mapper business for a long time now (almost 10 years, full time) and as it's a small world, we O/R mapper developers know almost all tricks to pull off by now: we all know what to do to make task ABC faster and what compromises (because there are almost always compromises) to deal with if we decide to make ABC faster that way. Some O/R mapper frameworks are faster in X, others in Y, but you can be sure the difference is mainly a result of a compromise some developers are willing to deal with and others aren't. That's why the O/R mapper frameworks on the market today are different in many ways, even though they all fetch and save entities from and to a database. I'm not suggesting there's no room for improvement in today's O/R mapper frameworks, there always is, but it's not a matter of 'the slowness of the application is caused by the O/R mapper' anymore. Perhaps query generation can be optimized a bit here, row materialization can be optimized a bit there, but it's mainly coming down to milliseconds. Still worth it if you're a framework developer, but it's not much compared to the time spend inside databases and in user code: if a complete fetch takes 40ms or 50ms (from call to entity object collection), it won't make a difference for your application as that 10ms difference won't be noticed. That's why it's very important to find the real locations of the problems so developers can fix them properly and don't get frustrated because their quest to get a fast, performing application failed. Performance tuning basics and rules Finding and fixing performance problems in any application is a strict procedure with four prescribed steps: isolate, analyze, interpret and fix, in that order. It's key that you don't skip a step nor make assumptions: these steps help you find the reason of a problem which seems to be there, and how to fix it or leave it as-is. Skipping a step, or when you assume things will be bad/slow without doing analysis will lead to the path of premature optimization and won't actually solve your problems, only create new ones. The most important rule of finding and fixing performance problems in software is that you have to understand what 'performance problem' actually means. Most developers will say "when a piece of software / code is slow, you have a performance problem". But is that actually the case? If I write a Linq query which will aggregate, group and sort 5 million rows from several tables to produce a resultset of 10 rows, it might take more than a couple of milliseconds before that resultset is ready to be consumed by other logic. If I solely look at the Linq query, the code consuming the resultset of the 10 rows and then look at the time it takes to complete the whole procedure, it will appear to me to be slow: all that time taken to produce and consume 10 rows? But if you look closer, if you analyze and interpret the situation, you'll see it does a tremendous amount of work, and in that light it might even be extremely fast. With every performance problem you encounter, always do realize that what you're trying to solve is perhaps not a technical problem at all, but a perception problem. The second most important rule you have to understand is based on the old saying "Penny wise, Pound Foolish": the part which takes e.g. 5% of the total time T for a given task isn't worth optimizing if you have another part which takes a much larger part of the total time T for that same given task. Optimizing parts which are relatively insignificant for the total time taken is not going to bring you better results overall, even if you totally optimize that part away. This is the core reason why analysis of the complete set of application parts which participate in a given task is key to being successful in solving performance problems: No analysis -> no problem -> no solution. One warning up front: hunting for performance will always include making compromises. Fast software can be made maintainable, but if you want to squeeze as much performance out of your software, you will inevitably be faced with the dilemma of compromising one or more from the group {readability, maintainability, features} for the extra performance you think you'll gain. It's then up to you to decide whether it's worth it. In almost all cases it's not. The reason for this is simple: the vast majority of performance problems can be solved by implementing the proper algorithms, the ones with proven Big O-characteristics so you know the performance you'll get plus you know the algorithm will work. The time taken by the algorithm implementing code is inevitable: you already implemented the best algorithm. You might find some optimizations on the technical level but in general these are minor. Let's look at the four steps to see how they guide us through the quest to find and fix performance problems. Isolate The first thing you need to do is to isolate the areas in your application which are assumed to be slow. For example, if your application is a web application and a given page is taking several seconds or even minutes to load, it's a good candidate to check out. It's important to start with the isolate step because it allows you to focus on a single code path per area with a clear begin and end and ignore the rest. The rest of the steps are taken per identified problematic area. Keep in mind that isolation focuses on tasks in an application, not code snippets. A task is something that's started in your application by either another task or the user, or another program, and has a beginning and an end. You can see a task as a piece of functionality offered by your application.  Analyze Once you've determined the problem areas, you have to perform analysis on the code paths of each area, to see where the performance problems occur and which areas are not the problem. This is a multi-layered effort: an application which uses an O/R mapper typically consists of multiple parts: there's likely some kind of interface (web, webservice, windows etc.), a part which controls the interface and business logic, the O/R mapper part and the RDBMS, all connected with either a network or inter-process connections provided by the OS or other means. Each of these parts, including the connectivity plumbing, eat up a part of the total time it takes to complete a task, e.g. load a webpage with all orders of a given customer X. To understand which parts participate in the task / area we're investigating and how much they contribute to the total time taken to complete the task, analysis of each participating task is essential. Start with the code you wrote which starts the task, analyze the code and track the path it follows through your application. What does the code do along the way, verify whether it's correct or not. Analyze whether you have implemented the right algorithms in your code for this particular area. Remember we're looking at one area at a time, which means we're ignoring all other code paths, just the code path of the current problematic area, from begin to end and back. Don't dig in and start optimizing at the code level just yet. We're just analyzing. If your analysis reveals big architectural stupidity, it's perhaps a good idea to rethink the architecture at this point. For the rest, we're analyzing which means we collect data about what could be wrong, for each participating part of the complete application. Reviewing the code you wrote is a good tool to get deeper understanding of what is going on for a given task but ultimately it lacks precision and overview what really happens: humans aren't good code interpreters, computers are. We therefore need to utilize tools to get deeper understanding about which parts contribute how much time to the total task, triggered by which other parts and for example how many times are they called. There are two different kind of tools which are necessary: .NET profilers and O/R mapper / RDBMS profilers. .NET profiling .NET profilers (e.g. dotTrace by JetBrains or Ants by Red Gate software) show exactly which pieces of code are called, how many times they're called, and the time it took to run that piece of code, at the method level and sometimes even at the line level. The .NET profilers are essential tools for understanding whether the time taken to complete a given task / area in your application is consumed by .NET code, where exactly in your code, the path to that code, how many times that code was called by other code and thus reveals where hotspots are located: the areas where a solution can be found. Importantly, they also reveal which areas can be left alone: remember our penny wise pound foolish saying: if a profiler reveals that a group of methods are fast, or don't contribute much to the total time taken for a given task, ignore them. Even if the code in them is perhaps complex and looks like a candidate for optimization: you can work all day on that, it won't matter.  As we're focusing on a single area of the application, it's best to start profiling right before you actually activate the task/area. Most .NET profilers support this by starting the application without starting the profiling procedure just yet. You navigate to the particular part which is slow, start profiling in the profiler, in your application you perform the actions which are considered slow, and afterwards you get a snapshot in the profiler. The snapshot contains the data collected by the profiler during the slow action, so most data is produced by code in the area to investigate. This is important, because it allows you to stay focused on a single area. O/R mapper and RDBMS profiling .NET profilers give you a good insight in the .NET side of things, but not in the RDBMS side of the application. As this article is about O/R mapper powered applications, we're also looking at databases, and the software making it possible to consume the database in your application: the O/R mapper. To understand which parts of the O/R mapper and database participate how much to the total time taken for task T, we need different tools. There are two kind of tools focusing on O/R mappers and database performance profiling: O/R mapper profilers and RDBMS profilers. For O/R mapper profilers, you can look at LLBLGen Prof by hibernating rhinos or the Linq to Sql/LLBLGen Pro profiler by Huagati. Hibernating rhinos also have profilers for other O/R mappers like NHibernate (NHProf) and Entity Framework (EFProf) and work the same as LLBLGen Prof. For RDBMS profilers, you have to look whether the RDBMS vendor has a profiler. For example for SQL Server, the profiler is shipped with SQL Server, for Oracle it's build into the RDBMS, however there are also 3rd party tools. Which tool you're using isn't really important, what's important is that you get insight in which queries are executed during the task / area we're currently focused on and how long they took. Here, the O/R mapper profilers have an advantage as they collect the time it took to execute the query from the application's perspective so they also collect the time it took to transport data across the network. This is important because a query which returns a massive resultset or a resultset with large blob/clob/ntext/image fields takes more time to get transported across the network than a small resultset and a database profiler doesn't take this into account most of the time. Another tool to use in this case, which is more low level and not all O/R mappers support it (though LLBLGen Pro and NHibernate as well do) is tracing: most O/R mappers offer some form of tracing or logging system which you can use to collect the SQL generated and executed and often also other activity behind the scenes. While tracing can produce a tremendous amount of data in some cases, it also gives insight in what's going on. Interpret After we've completed the analysis step it's time to look at the data we've collected. We've done code reviews to see whether we've done anything stupid and which parts actually take place and if the proper algorithms have been implemented. We've done .NET profiling to see which parts are choke points and how much time they contribute to the total time taken to complete the task we're investigating. We've performed O/R mapper profiling and RDBMS profiling to see which queries were executed during the task, how many queries were generated and executed and how long they took to complete, including network transportation. All this data reveals two things: which parts are big contributors to the total time taken and which parts are irrelevant. Both aspects are very important. The parts which are irrelevant (i.e. don't contribute significantly to the total time taken) can be ignored from now on, we won't look at them. The parts which contribute a lot to the total time taken are important to look at. We now have to first look at the .NET profiler results, to see whether the time taken is consumed in our own code, in .NET framework code, in the O/R mapper itself or somewhere else. For example if most of the time is consumed by DbCommand.ExecuteReader, the time it took to complete the task is depending on the time the data is fetched from the database. If there was just 1 query executed, according to tracing or O/R mapper profilers / RDBMS profilers, check whether that query is optimal, uses indexes or has to deal with a lot of data. Interpret means that you follow the path from begin to end through the data collected and determine where, along the path, the most time is contributed. It also means that you have to check whether this was expected or is totally unexpected. My previous example of the 10 row resultset of a query which groups millions of rows will likely reveal that a long time is spend inside the database and almost no time is spend in the .NET code, meaning the RDBMS part contributes the most to the total time taken, the rest is compared to that time, irrelevant. Considering the vastness of the source data set, it's expected this will take some time. However, does it need tweaking? Perhaps all possible tweaks are already in place. In the interpret step you then have to decide that further action in this area is necessary or not, based on what the analysis results show: if the analysis results were unexpected and in the area where the most time is contributed to the total time taken is room for improvement, action should be taken. If not, you can only accept the situation and move on. In all cases, document your decision together with the analysis you've done. If you decide that the perceived performance problem is actually expected due to the nature of the task performed, it's essential that in the future when someone else looks at the application and starts asking questions you can answer them properly and new analysis is only necessary if situations changed. Fix After interpreting the analysis results you've concluded that some areas need adjustment. This is the fix step: you're actively correcting the performance problem with proper action targeted at the real cause. In many cases related to O/R mapper powered applications it means you'll use different features of the O/R mapper to achieve the same goal, or apply optimizations at the RDBMS level. It could also mean you apply caching inside your application (compromise memory consumption over performance) to avoid unnecessary re-querying data and re-consuming the results. After applying a change, it's key you re-do the analysis and interpretation steps: compare the results and expectations with what you had before, to see whether your actions had any effect or whether it moved the problem to a different part of the application. Don't fall into the trap to do partly analysis: do the full analysis again: .NET profiling and O/R mapper / RDBMS profiling. It might very well be that the changes you've made make one part faster but another part significantly slower, in such a way that the overall problem hasn't changed at all. Performance tuning is dealing with compromises and making choices: to use one feature over the other, to accept a higher memory footprint, to go away from the strict-OO path and execute queries directly onto the RDBMS, these are choices and compromises which will cross your path if you want to fix performance problems with respect to O/R mappers or data-access and databases in general. In most cases it's not a big issue: alternatives are often good choices too and the compromises aren't that hard to deal with. What is important is that you document why you made a choice, a compromise: which analysis data, which interpretation led you to the choice made. This is key for good maintainability in the years to come. Most common performance problems with O/R mappers Below is an incomplete list of common performance problems related to data-access / O/R mappers / RDBMS code. It will help you with fixing the hotspots you found in the interpretation step. SELECT N+1: (Lazy-loading specific). Lazy loading triggered performance bottlenecks. Consider a list of Orders bound to a grid. You have a Field mapped onto a related field in Order, Customer.CompanyName. Showing this column in the grid will make the grid fetch (indirectly) for each row the Customer row. This means you'll get for the single list not 1 query (for the orders) but 1+(the number of orders shown) queries. To solve this: use eager loading using a prefetch path to fetch the customers with the orders. SELECT N+1 is easy to spot with an O/R mapper profiler or RDBMS profiler: if you see a lot of identical queries executed at once, you have this problem. Prefetch paths using many path nodes or sorting, or limiting. Eager loading problem. Prefetch paths can help with performance, but as 1 query is fetched per node, it can be the number of data fetched in a child node is bigger than you think. Also consider that data in every node is merged on the client within the parent. This is fast, but it also can take some time if you fetch massive amounts of entities. If you keep fetches small, you can use tuning parameters like the ParameterizedPrefetchPathThreshold setting to get more optimal queries. Deep inheritance hierarchies of type Target Per Entity/Type. If you use inheritance of type Target per Entity / Type (each type in the inheritance hierarchy is mapped onto its own table/view), fetches will join subtype- and supertype tables in many cases, which can lead to a lot of performance problems if the hierarchy has many types. With this problem, keep inheritance to a minimum if possible, or switch to a hierarchy of type Target Per Hierarchy, which means all entities in the inheritance hierarchy are mapped onto the same table/view. Of course this has its own set of drawbacks, but it's a compromise you might want to take. Fetching massive amounts of data by fetching large lists of entities. LLBLGen Pro supports paging (and limiting the # of rows returned), which is often key to process through large sets of data. Use paging on the RDBMS if possible (so a query is executed which returns only the rows in the page requested). When using paging in a web application, be sure that you switch server-side paging on on the datasourcecontrol used. In this case, paging on the grid alone is not enough: this can lead to fetching a lot of data which is then loaded into the grid and paged there. Keep note that analyzing queries for paging could lead to the false assumption that paging doesn't occur, e.g. when the query contains a field of type ntext/image/clob/blob and DISTINCT can't be applied while it should have (e.g. due to a join): the datareader will do DISTINCT filtering on the client. this is a little slower but it does perform paging functionality on the data-reader so it won't fetch all rows even if the query suggests it does. Fetch massive amounts of data because blob/clob/ntext/image fields aren't excluded. LLBLGen Pro supports field exclusion for queries. You can exclude fields (also in prefetch paths) per query to avoid fetching all fields of an entity, e.g. when you don't need them for the logic consuming the resultset. Excluding fields can greatly reduce the amount of time spend on data-transport across the network. Use this optimization if you see that there's a big difference between query execution time on the RDBMS and the time reported by the .NET profiler for the ExecuteReader method call. Doing client-side aggregates/scalar calculations by consuming a lot of data. If possible, try to formulate a scalar query or group by query using the projection system or GetScalar functionality of LLBLGen Pro to do data consumption on the RDBMS server. It's far more efficient to process data on the RDBMS server than to first load it all in memory, then traverse the data in-memory to calculate a value. Using .ToList() constructs inside linq queries. It might be you use .ToList() somewhere in a Linq query which makes the query be run partially in-memory. Example: var q = from c in metaData.Customers.ToList() where c.Country=="Norway" select c; This will actually fetch all customers in-memory and do an in-memory filtering, as the linq query is defined on an IEnumerable<T>, and not on the IQueryable<T>. Linq is nice, but it can often be a bit unclear where some parts of a Linq query might run. Fetching all entities to delete into memory first. To delete a set of entities it's rather inefficient to first fetch them all into memory and then delete them one by one. It's more efficient to execute a DELETE FROM ... WHERE query on the database directly to delete the entities in one go. LLBLGen Pro supports this feature, and so do some other O/R mappers. It's not always possible to do this operation in the context of an O/R mapper however: if an O/R mapper relies on a cache, these kind of operations are likely not supported because they make it impossible to track whether an entity is actually removed from the DB and thus can be removed from the cache. Fetching all entities to update with an expression into memory first. Similar to the previous point: it is more efficient to update a set of entities directly with a single UPDATE query using an expression instead of fetching the entities into memory first and then updating the entities in a loop, and afterwards saving them. It might however be a compromise you don't want to take as it is working around the idea of having an object graph in memory which is manipulated and instead makes the code fully aware there's a RDBMS somewhere. Conclusion Performance tuning is almost always about compromises and making choices. It's also about knowing where to look and how the systems in play behave and should behave. The four steps I provided should help you stay focused on the real problem and lead you towards the solution. Knowing how to optimally use the systems participating in your own code (.NET framework, O/R mapper, RDBMS, network/services) is key for success as well as knowing what's going on inside the application you built. I hope you'll find this guide useful in tracking down performance problems and dealing with them in a useful way.  

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  • Advanced TSQL Tuning: Why Internals Knowledge Matters

    - by Paul White
    There is much more to query tuning than reducing logical reads and adding covering nonclustered indexes.  Query tuning is not complete as soon as the query returns results quickly in the development or test environments.  In production, your query will compete for memory, CPU, locks, I/O and other resources on the server.  Today’s entry looks at some tuning considerations that are often overlooked, and shows how deep internals knowledge can help you write better TSQL. As always, we’ll need some example data.  In fact, we are going to use three tables today, each of which is structured like this: Each table has 50,000 rows made up of an INTEGER id column and a padding column containing 3,999 characters in every row.  The only difference between the three tables is in the type of the padding column: the first table uses CHAR(3999), the second uses VARCHAR(MAX), and the third uses the deprecated TEXT type.  A script to create a database with the three tables and load the sample data follows: USE master; GO IF DB_ID('SortTest') IS NOT NULL DROP DATABASE SortTest; GO CREATE DATABASE SortTest COLLATE LATIN1_GENERAL_BIN; GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest', SIZE = 3GB, MAXSIZE = 3GB ); GO ALTER DATABASE SortTest MODIFY FILE ( NAME = 'SortTest_log', SIZE = 256MB, MAXSIZE = 1GB, FILEGROWTH = 128MB ); GO ALTER DATABASE SortTest SET ALLOW_SNAPSHOT_ISOLATION OFF ; ALTER DATABASE SortTest SET AUTO_CLOSE OFF ; ALTER DATABASE SortTest SET AUTO_CREATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_SHRINK OFF ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS ON ; ALTER DATABASE SortTest SET AUTO_UPDATE_STATISTICS_ASYNC ON ; ALTER DATABASE SortTest SET PARAMETERIZATION SIMPLE ; ALTER DATABASE SortTest SET READ_COMMITTED_SNAPSHOT OFF ; ALTER DATABASE SortTest SET MULTI_USER ; ALTER DATABASE SortTest SET RECOVERY SIMPLE ; USE SortTest; GO CREATE TABLE dbo.TestCHAR ( id INTEGER IDENTITY (1,1) NOT NULL, padding CHAR(3999) NOT NULL,   CONSTRAINT [PK dbo.TestCHAR (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestMAX ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAX (id)] PRIMARY KEY CLUSTERED (id), ) ; CREATE TABLE dbo.TestTEXT ( id INTEGER IDENTITY (1,1) NOT NULL, padding TEXT NOT NULL,   CONSTRAINT [PK dbo.TestTEXT (id)] PRIMARY KEY CLUSTERED (id), ) ; -- ============= -- Load TestCHAR (about 3s) -- ============= INSERT INTO dbo.TestCHAR WITH (TABLOCKX) ( padding ) SELECT padding = REPLICATE(CHAR(65 + (Data.n % 26)), 3999) FROM ( SELECT TOP (50000) n = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) - 1 FROM master.sys.columns C1, master.sys.columns C2, master.sys.columns C3 ORDER BY n ASC ) AS Data ORDER BY Data.n ASC ; -- ============ -- Load TestMAX (about 3s) -- ============ INSERT INTO dbo.TestMAX WITH (TABLOCKX) ( padding ) SELECT CONVERT(VARCHAR(MAX), padding) FROM dbo.TestCHAR ORDER BY id ; -- ============= -- Load TestTEXT (about 5s) -- ============= INSERT INTO dbo.TestTEXT WITH (TABLOCKX) ( padding ) SELECT CONVERT(TEXT, padding) FROM dbo.TestCHAR ORDER BY id ; -- ========== -- Space used -- ========== -- EXECUTE sys.sp_spaceused @objname = 'dbo.TestCHAR'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAX'; EXECUTE sys.sp_spaceused @objname = 'dbo.TestTEXT'; ; CHECKPOINT ; That takes around 15 seconds to run, and shows the space allocated to each table in its output: To illustrate the points I want to make today, the example task we are going to set ourselves is to return a random set of 150 rows from each table.  The basic shape of the test query is the same for each of the three test tables: SELECT TOP (150) T.id, T.padding FROM dbo.Test AS T ORDER BY NEWID() OPTION (MAXDOP 1) ; Test 1 – CHAR(3999) Running the template query shown above using the TestCHAR table as the target, we find that the query takes around 5 seconds to return its results.  This seems slow, considering that the table only has 50,000 rows.  Working on the assumption that generating a GUID for each row is a CPU-intensive operation, we might try enabling parallelism to see if that speeds up the response time.  Running the query again (but without the MAXDOP 1 hint) on a machine with eight logical processors, the query now takes 10 seconds to execute – twice as long as when run serially. Rather than attempting further guesses at the cause of the slowness, let’s go back to serial execution and add some monitoring.  The script below monitors STATISTICS IO output and the amount of tempdb used by the test query.  We will also run a Profiler trace to capture any warnings generated during query execution. DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TC.id, TC.padding FROM dbo.TestCHAR AS TC ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; Let’s take a closer look at the statistics and query plan generated from this: Following the flow of the data from right to left, we see the expected 50,000 rows emerging from the Clustered Index Scan, with a total estimated size of around 191MB.  The Compute Scalar adds a column containing a random GUID (generated from the NEWID() function call) for each row.  With this extra column in place, the size of the data arriving at the Sort operator is estimated to be 192MB. Sort is a blocking operator – it has to examine all of the rows on its input before it can produce its first row of output (the last row received might sort first).  This characteristic means that Sort requires a memory grant – memory allocated for the query’s use by SQL Server just before execution starts.  In this case, the Sort is the only memory-consuming operator in the plan, so it has access to the full 243MB (248,696KB) of memory reserved by SQL Server for this query execution. Notice that the memory grant is significantly larger than the expected size of the data to be sorted.  SQL Server uses a number of techniques to speed up sorting, some of which sacrifice size for comparison speed.  Sorts typically require a very large number of comparisons, so this is usually a very effective optimization.  One of the drawbacks is that it is not possible to exactly predict the sort space needed, as it depends on the data itself.  SQL Server takes an educated guess based on data types, sizes, and the number of rows expected, but the algorithm is not perfect. In spite of the large memory grant, the Profiler trace shows a Sort Warning event (indicating that the sort ran out of memory), and the tempdb usage monitor shows that 195MB of tempdb space was used – all of that for system use.  The 195MB represents physical write activity on tempdb, because SQL Server strictly enforces memory grants – a query cannot ‘cheat’ and effectively gain extra memory by spilling to tempdb pages that reside in memory.  Anyway, the key point here is that it takes a while to write 195MB to disk, and this is the main reason that the query takes 5 seconds overall. If you are wondering why using parallelism made the problem worse, consider that eight threads of execution result in eight concurrent partial sorts, each receiving one eighth of the memory grant.  The eight sorts all spilled to tempdb, resulting in inefficiencies as the spilled sorts competed for disk resources.  More importantly, there are specific problems at the point where the eight partial results are combined, but I’ll cover that in a future post. CHAR(3999) Performance Summary: 5 seconds elapsed time 243MB memory grant 195MB tempdb usage 192MB estimated sort set 25,043 logical reads Sort Warning Test 2 – VARCHAR(MAX) We’ll now run exactly the same test (with the additional monitoring) on the table using a VARCHAR(MAX) padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TM.id, TM.padding FROM dbo.TestMAX AS TM ORDER BY NEWID() OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query takes around 8 seconds to complete (3 seconds longer than Test 1).  Notice that the estimated row and data sizes are very slightly larger, and the overall memory grant has also increased very slightly to 245MB.  The most marked difference is in the amount of tempdb space used – this query wrote almost 391MB of sort run data to the physical tempdb file.  Don’t draw any general conclusions about VARCHAR(MAX) versus CHAR from this – I chose the length of the data specifically to expose this edge case.  In most cases, VARCHAR(MAX) performs very similarly to CHAR – I just wanted to make test 2 a bit more exciting. MAX Performance Summary: 8 seconds elapsed time 245MB memory grant 391MB tempdb usage 193MB estimated sort set 25,043 logical reads Sort warning Test 3 – TEXT The same test again, but using the deprecated TEXT data type for the padding column: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) TT.id, TT.padding FROM dbo.TestTEXT AS TT ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; This time the query runs in 500ms.  If you look at the metrics we have been checking so far, it’s not hard to understand why: TEXT Performance Summary: 0.5 seconds elapsed time 9MB memory grant 5MB tempdb usage 5MB estimated sort set 207 logical reads 596 LOB logical reads Sort warning SQL Server’s memory grant algorithm still underestimates the memory needed to perform the sorting operation, but the size of the data to sort is so much smaller (5MB versus 193MB previously) that the spilled sort doesn’t matter very much.  Why is the data size so much smaller?  The query still produces the correct results – including the large amount of data held in the padding column – so what magic is being performed here? TEXT versus MAX Storage The answer lies in how columns of the TEXT data type are stored.  By default, TEXT data is stored off-row in separate LOB pages – which explains why this is the first query we have seen that records LOB logical reads in its STATISTICS IO output.  You may recall from my last post that LOB data leaves an in-row pointer to the separate storage structure holding the LOB data. SQL Server can see that the full LOB value is not required by the query plan until results are returned, so instead of passing the full LOB value down the plan from the Clustered Index Scan, it passes the small in-row structure instead.  SQL Server estimates that each row coming from the scan will be 79 bytes long – 11 bytes for row overhead, 4 bytes for the integer id column, and 64 bytes for the LOB pointer (in fact the pointer is rather smaller – usually 16 bytes – but the details of that don’t really matter right now). OK, so this query is much more efficient because it is sorting a very much smaller data set – SQL Server delays retrieving the LOB data itself until after the Sort starts producing its 150 rows.  The question that normally arises at this point is: Why doesn’t SQL Server use the same trick when the padding column is defined as VARCHAR(MAX)? The answer is connected with the fact that if the actual size of the VARCHAR(MAX) data is 8000 bytes or less, it is usually stored in-row in exactly the same way as for a VARCHAR(8000) column – MAX data only moves off-row into LOB storage when it exceeds 8000 bytes.  The default behaviour of the TEXT type is to be stored off-row by default, unless the ‘text in row’ table option is set suitably and there is room on the page.  There is an analogous (but opposite) setting to control the storage of MAX data – the ‘large value types out of row’ table option.  By enabling this option for a table, MAX data will be stored off-row (in a LOB structure) instead of in-row.  SQL Server Books Online has good coverage of both options in the topic In Row Data. The MAXOOR Table The essential difference, then, is that MAX defaults to in-row storage, and TEXT defaults to off-row (LOB) storage.  You might be thinking that we could get the same benefits seen for the TEXT data type by storing the VARCHAR(MAX) values off row – so let’s look at that option now.  This script creates a fourth table, with the VARCHAR(MAX) data stored off-row in LOB pages: CREATE TABLE dbo.TestMAXOOR ( id INTEGER IDENTITY (1,1) NOT NULL, padding VARCHAR(MAX) NOT NULL,   CONSTRAINT [PK dbo.TestMAXOOR (id)] PRIMARY KEY CLUSTERED (id), ) ; EXECUTE sys.sp_tableoption @TableNamePattern = N'dbo.TestMAXOOR', @OptionName = 'large value types out of row', @OptionValue = 'true' ; SELECT large_value_types_out_of_row FROM sys.tables WHERE [schema_id] = SCHEMA_ID(N'dbo') AND name = N'TestMAXOOR' ; INSERT INTO dbo.TestMAXOOR WITH (TABLOCKX) ( padding ) SELECT SPACE(0) FROM dbo.TestCHAR ORDER BY id ; UPDATE TM WITH (TABLOCK) SET padding.WRITE (TC.padding, NULL, NULL) FROM dbo.TestMAXOOR AS TM JOIN dbo.TestCHAR AS TC ON TC.id = TM.id ; EXECUTE sys.sp_spaceused @objname = 'dbo.TestMAXOOR' ; CHECKPOINT ; Test 4 – MAXOOR We can now re-run our test on the MAXOOR (MAX out of row) table: DECLARE @read BIGINT, @write BIGINT ; SELECT @read = SUM(num_of_bytes_read), @write = SUM(num_of_bytes_written) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; SET STATISTICS IO ON ; SELECT TOP (150) MO.id, MO.padding FROM dbo.TestMAXOOR AS MO ORDER BY NEWID() OPTION (MAXDOP 1, RECOMPILE) ; SET STATISTICS IO OFF ; SELECT tempdb_read_MB = (SUM(num_of_bytes_read) - @read) / 1024. / 1024., tempdb_write_MB = (SUM(num_of_bytes_written) - @write) / 1024. / 1024., internal_use_MB = ( SELECT internal_objects_alloc_page_count / 128.0 FROM sys.dm_db_task_space_usage WHERE session_id = @@SPID ) FROM tempdb.sys.database_files AS DBF JOIN sys.dm_io_virtual_file_stats(2, NULL) AS FS ON FS.file_id = DBF.file_id WHERE DBF.type_desc = 'ROWS' ; TEXT Performance Summary: 0.3 seconds elapsed time 245MB memory grant 0MB tempdb usage 193MB estimated sort set 207 logical reads 446 LOB logical reads No sort warning The query runs very quickly – slightly faster than Test 3, and without spilling the sort to tempdb (there is no sort warning in the trace, and the monitoring query shows zero tempdb usage by this query).  SQL Server is passing the in-row pointer structure down the plan and only looking up the LOB value on the output side of the sort. The Hidden Problem There is still a huge problem with this query though – it requires a 245MB memory grant.  No wonder the sort doesn’t spill to tempdb now – 245MB is about 20 times more memory than this query actually requires to sort 50,000 records containing LOB data pointers.  Notice that the estimated row and data sizes in the plan are the same as in test 2 (where the MAX data was stored in-row). The optimizer assumes that MAX data is stored in-row, regardless of the sp_tableoption setting ‘large value types out of row’.  Why?  Because this option is dynamic – changing it does not immediately force all MAX data in the table in-row or off-row, only when data is added or actually changed.  SQL Server does not keep statistics to show how much MAX or TEXT data is currently in-row, and how much is stored in LOB pages.  This is an annoying limitation, and one which I hope will be addressed in a future version of the product. So why should we worry about this?  Excessive memory grants reduce concurrency and may result in queries waiting on the RESOURCE_SEMAPHORE wait type while they wait for memory they do not need.  245MB is an awful lot of memory, especially on 32-bit versions where memory grants cannot use AWE-mapped memory.  Even on a 64-bit server with plenty of memory, do you really want a single query to consume 0.25GB of memory unnecessarily?  That’s 32,000 8KB pages that might be put to much better use. The Solution The answer is not to use the TEXT data type for the padding column.  That solution happens to have better performance characteristics for this specific query, but it still results in a spilled sort, and it is hard to recommend the use of a data type which is scheduled for removal.  I hope it is clear to you that the fundamental problem here is that SQL Server sorts the whole set arriving at a Sort operator.  Clearly, it is not efficient to sort the whole table in memory just to return 150 rows in a random order. The TEXT example was more efficient because it dramatically reduced the size of the set that needed to be sorted.  We can do the same thing by selecting 150 unique keys from the table at random (sorting by NEWID() for example) and only then retrieving the large padding column values for just the 150 rows we need.  The following script implements that idea for all four tables: SET STATISTICS IO ON ; WITH TestTable AS ( SELECT * FROM dbo.TestCHAR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id = ANY (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAX ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestTEXT ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; WITH TestTable AS ( SELECT * FROM dbo.TestMAXOOR ), TopKeys AS ( SELECT TOP (150) id FROM TestTable ORDER BY NEWID() ) SELECT T1.id, T1.padding FROM TestTable AS T1 WHERE T1.id IN (SELECT id FROM TopKeys) OPTION (MAXDOP 1) ; SET STATISTICS IO OFF ; All four queries now return results in much less than a second, with memory grants between 6 and 12MB, and without spilling to tempdb.  The small remaining inefficiency is in reading the id column values from the clustered primary key index.  As a clustered index, it contains all the in-row data at its leaf.  The CHAR and VARCHAR(MAX) tables store the padding column in-row, so id values are separated by a 3999-character column, plus row overhead.  The TEXT and MAXOOR tables store the padding values off-row, so id values in the clustered index leaf are separated by the much-smaller off-row pointer structure.  This difference is reflected in the number of logical page reads performed by the four queries: Table 'TestCHAR' logical reads 25511 lob logical reads 000 Table 'TestMAX'. logical reads 25511 lob logical reads 000 Table 'TestTEXT' logical reads 00412 lob logical reads 597 Table 'TestMAXOOR' logical reads 00413 lob logical reads 446 We can increase the density of the id values by creating a separate nonclustered index on the id column only.  This is the same key as the clustered index, of course, but the nonclustered index will not include the rest of the in-row column data. CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestCHAR (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAX (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestTEXT (id); CREATE UNIQUE NONCLUSTERED INDEX uq1 ON dbo.TestMAXOOR (id); The four queries can now use the very dense nonclustered index to quickly scan the id values, sort them by NEWID(), select the 150 ids we want, and then look up the padding data.  The logical reads with the new indexes in place are: Table 'TestCHAR' logical reads 835 lob logical reads 0 Table 'TestMAX' logical reads 835 lob logical reads 0 Table 'TestTEXT' logical reads 686 lob logical reads 597 Table 'TestMAXOOR' logical reads 686 lob logical reads 448 With the new index, all four queries use the same query plan (click to enlarge): Performance Summary: 0.3 seconds elapsed time 6MB memory grant 0MB tempdb usage 1MB sort set 835 logical reads (CHAR, MAX) 686 logical reads (TEXT, MAXOOR) 597 LOB logical reads (TEXT) 448 LOB logical reads (MAXOOR) No sort warning I’ll leave it as an exercise for the reader to work out why trying to eliminate the Key Lookup by adding the padding column to the new nonclustered indexes would be a daft idea Conclusion This post is not about tuning queries that access columns containing big strings.  It isn’t about the internal differences between TEXT and MAX data types either.  It isn’t even about the cool use of UPDATE .WRITE used in the MAXOOR table load.  No, this post is about something else: Many developers might not have tuned our starting example query at all – 5 seconds isn’t that bad, and the original query plan looks reasonable at first glance.  Perhaps the NEWID() function would have been blamed for ‘just being slow’ – who knows.  5 seconds isn’t awful – unless your users expect sub-second responses – but using 250MB of memory and writing 200MB to tempdb certainly is!  If ten sessions ran that query at the same time in production that’s 2.5GB of memory usage and 2GB hitting tempdb.  Of course, not all queries can be rewritten to avoid large memory grants and sort spills using the key-lookup technique in this post, but that’s not the point either. The point of this post is that a basic understanding of execution plans is not enough.  Tuning for logical reads and adding covering indexes is not enough.  If you want to produce high-quality, scalable TSQL that won’t get you paged as soon as it hits production, you need a deep understanding of execution plans, and as much accurate, deep knowledge about SQL Server as you can lay your hands on.  The advanced database developer has a wide range of tools to use in writing queries that perform well in a range of circumstances. By the way, the examples in this post were written for SQL Server 2008.  They will run on 2005 and demonstrate the same principles, but you won’t get the same figures I did because 2005 had a rather nasty bug in the Top N Sort operator.  Fair warning: if you do decide to run the scripts on a 2005 instance (particularly the parallel query) do it before you head out for lunch… This post is dedicated to the people of Christchurch, New Zealand. © 2011 Paul White email: @[email protected] twitter: @SQL_Kiwi

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  • Understanding G1 GC Logs

    - by poonam
    The purpose of this post is to explain the meaning of GC logs generated with some tracing and diagnostic options for G1 GC. We will take a look at the output generated with PrintGCDetails which is a product flag and provides the most detailed level of information. Along with that, we will also look at the output of two diagnostic flags that get enabled with -XX:+UnlockDiagnosticVMOptions option - G1PrintRegionLivenessInfo that prints the occupancy and the amount of space used by live objects in each region at the end of the marking cycle and G1PrintHeapRegions that provides detailed information on the heap regions being allocated and reclaimed. We will be looking at the logs generated with JDK 1.7.0_04 using these options. Option -XX:+PrintGCDetails Here's a sample log of G1 collection generated with PrintGCDetails. 0.522: [GC pause (young), 0.15877971 secs] [Parallel Time: 157.1 ms] [GC Worker Start (ms): 522.1 522.2 522.2 522.2 Avg: 522.2, Min: 522.1, Max: 522.2, Diff: 0.1] [Ext Root Scanning (ms): 1.6 1.5 1.6 1.9 Avg: 1.7, Min: 1.5, Max: 1.9, Diff: 0.4] [Update RS (ms): 38.7 38.8 50.6 37.3 Avg: 41.3, Min: 37.3, Max: 50.6, Diff: 13.3] [Processed Buffers : 2 2 3 2 Sum: 9, Avg: 2, Min: 2, Max: 3, Diff: 1] [Scan RS (ms): 9.9 9.7 0.0 9.7 Avg: 7.3, Min: 0.0, Max: 9.9, Diff: 9.9] [Object Copy (ms): 106.7 106.8 104.6 107.9 Avg: 106.5, Min: 104.6, Max: 107.9, Diff: 3.3] [Termination (ms): 0.0 0.0 0.0 0.0 Avg: 0.0, Min: 0.0, Max: 0.0, Diff: 0.0] [Termination Attempts : 1 4 4 6 Sum: 15, Avg: 3, Min: 1, Max: 6, Diff: 5] [GC Worker End (ms): 679.1 679.1 679.1 679.1 Avg: 679.1, Min: 679.1, Max: 679.1, Diff: 0.1] [GC Worker (ms): 156.9 157.0 156.9 156.9 Avg: 156.9, Min: 156.9, Max: 157.0, Diff: 0.1] [GC Worker Other (ms): 0.3 0.3 0.3 0.3 Avg: 0.3, Min: 0.3, Max: 0.3, Diff: 0.0] [Clear CT: 0.1 ms] [Other: 1.5 ms] [Choose CSet: 0.0 ms] [Ref Proc: 0.3 ms] [Ref Enq: 0.0 ms] [Free CSet: 0.3 ms] [Eden: 12M(12M)->0B(10M) Survivors: 0B->2048K Heap: 13M(64M)->9739K(64M)] [Times: user=0.59 sys=0.02, real=0.16 secs] This is the typical log of an Evacuation Pause (G1 collection) in which live objects are copied from one set of regions (young OR young+old) to another set. It is a stop-the-world activity and all the application threads are stopped at a safepoint during this time. This pause is made up of several sub-tasks indicated by the indentation in the log entries. Here's is the top most line that gets printed for the Evacuation Pause. 0.522: [GC pause (young), 0.15877971 secs] This is the highest level information telling us that it is an Evacuation Pause that started at 0.522 secs from the start of the process, in which all the regions being evacuated are Young i.e. Eden and Survivor regions. This collection took 0.15877971 secs to finish. Evacuation Pauses can be mixed as well. In which case the set of regions selected include all of the young regions as well as some old regions. 1.730: [GC pause (mixed), 0.32714353 secs] Let's take a look at all the sub-tasks performed in this Evacuation Pause. [Parallel Time: 157.1 ms] Parallel Time is the total elapsed time spent by all the parallel GC worker threads. The following lines correspond to the parallel tasks performed by these worker threads in this total parallel time, which in this case is 157.1 ms. [GC Worker Start (ms): 522.1 522.2 522.2 522.2Avg: 522.2, Min: 522.1, Max: 522.2, Diff: 0.1] The first line tells us the start time of each of the worker thread in milliseconds. The start times are ordered with respect to the worker thread ids – thread 0 started at 522.1ms and thread 1 started at 522.2ms from the start of the process. The second line tells the Avg, Min, Max and Diff of the start times of all of the worker threads. [Ext Root Scanning (ms): 1.6 1.5 1.6 1.9 Avg: 1.7, Min: 1.5, Max: 1.9, Diff: 0.4] This gives us the time spent by each worker thread scanning the roots (globals, registers, thread stacks and VM data structures). Here, thread 0 took 1.6ms to perform the root scanning task and thread 1 took 1.5 ms. The second line clearly shows the Avg, Min, Max and Diff of the times spent by all the worker threads. [Update RS (ms): 38.7 38.8 50.6 37.3 Avg: 41.3, Min: 37.3, Max: 50.6, Diff: 13.3] Update RS gives us the time each thread spent in updating the Remembered Sets. Remembered Sets are the data structures that keep track of the references that point into a heap region. Mutator threads keep changing the object graph and thus the references that point into a particular region. We keep track of these changes in buffers called Update Buffers. The Update RS sub-task processes the update buffers that were not able to be processed concurrently, and updates the corresponding remembered sets of all regions. [Processed Buffers : 2 2 3 2Sum: 9, Avg: 2, Min: 2, Max: 3, Diff: 1] This tells us the number of Update Buffers (mentioned above) processed by each worker thread. [Scan RS (ms): 9.9 9.7 0.0 9.7 Avg: 7.3, Min: 0.0, Max: 9.9, Diff: 9.9] These are the times each worker thread had spent in scanning the Remembered Sets. Remembered Set of a region contains cards that correspond to the references pointing into that region. This phase scans those cards looking for the references pointing into all the regions of the collection set. [Object Copy (ms): 106.7 106.8 104.6 107.9 Avg: 106.5, Min: 104.6, Max: 107.9, Diff: 3.3] These are the times spent by each worker thread copying live objects from the regions in the Collection Set to the other regions. [Termination (ms): 0.0 0.0 0.0 0.0 Avg: 0.0, Min: 0.0, Max: 0.0, Diff: 0.0] Termination time is the time spent by the worker thread offering to terminate. But before terminating, it checks the work queues of other threads and if there are still object references in other work queues, it tries to steal object references, and if it succeeds in stealing a reference, it processes that and offers to terminate again. [Termination Attempts : 1 4 4 6 Sum: 15, Avg: 3, Min: 1, Max: 6, Diff: 5] This gives the number of times each thread has offered to terminate. [GC Worker End (ms): 679.1 679.1 679.1 679.1 Avg: 679.1, Min: 679.1, Max: 679.1, Diff: 0.1] These are the times in milliseconds at which each worker thread stopped. [GC Worker (ms): 156.9 157.0 156.9 156.9 Avg: 156.9, Min: 156.9, Max: 157.0, Diff: 0.1] These are the total lifetimes of each worker thread. [GC Worker Other (ms): 0.3 0.3 0.3 0.3Avg: 0.3, Min: 0.3, Max: 0.3, Diff: 0.0] These are the times that each worker thread spent in performing some other tasks that we have not accounted above for the total Parallel Time. [Clear CT: 0.1 ms] This is the time spent in clearing the Card Table. This task is performed in serial mode. [Other: 1.5 ms] Time spent in the some other tasks listed below. The following sub-tasks (which individually may be parallelized) are performed serially. [Choose CSet: 0.0 ms] Time spent in selecting the regions for the Collection Set. [Ref Proc: 0.3 ms] Total time spent in processing Reference objects. [Ref Enq: 0.0 ms] Time spent in enqueuing references to the ReferenceQueues. [Free CSet: 0.3 ms] Time spent in freeing the collection set data structure. [Eden: 12M(12M)->0B(13M) Survivors: 0B->2048K Heap: 14M(64M)->9739K(64M)] This line gives the details on the heap size changes with the Evacuation Pause. This shows that Eden had the occupancy of 12M and its capacity was also 12M before the collection. After the collection, its occupancy got reduced to 0 since everything is evacuated/promoted from Eden during a collection, and its target size grew to 13M. The new Eden capacity of 13M is not reserved at this point. This value is the target size of the Eden. Regions are added to Eden as the demand is made and when the added regions reach to the target size, we start the next collection. Similarly, Survivors had the occupancy of 0 bytes and it grew to 2048K after the collection. The total heap occupancy and capacity was 14M and 64M receptively before the collection and it became 9739K and 64M after the collection. Apart from the evacuation pauses, G1 also performs concurrent-marking to build the live data information of regions. 1.416: [GC pause (young) (initial-mark), 0.62417980 secs] ….... 2.042: [GC concurrent-root-region-scan-start] 2.067: [GC concurrent-root-region-scan-end, 0.0251507] 2.068: [GC concurrent-mark-start] 3.198: [GC concurrent-mark-reset-for-overflow] 4.053: [GC concurrent-mark-end, 1.9849672 sec] 4.055: [GC remark 4.055: [GC ref-proc, 0.0000254 secs], 0.0030184 secs] [Times: user=0.00 sys=0.00, real=0.00 secs] 4.088: [GC cleanup 117M->106M(138M), 0.0015198 secs] [Times: user=0.00 sys=0.00, real=0.00 secs] 4.090: [GC concurrent-cleanup-start] 4.091: [GC concurrent-cleanup-end, 0.0002721] The first phase of a marking cycle is Initial Marking where all the objects directly reachable from the roots are marked and this phase is piggy-backed on a fully young Evacuation Pause. 2.042: [GC concurrent-root-region-scan-start] This marks the start of a concurrent phase that scans the set of root-regions which are directly reachable from the survivors of the initial marking phase. 2.067: [GC concurrent-root-region-scan-end, 0.0251507] End of the concurrent root region scan phase and it lasted for 0.0251507 seconds. 2.068: [GC concurrent-mark-start] Start of the concurrent marking at 2.068 secs from the start of the process. 3.198: [GC concurrent-mark-reset-for-overflow] This indicates that the global marking stack had became full and there was an overflow of the stack. Concurrent marking detected this overflow and had to reset the data structures to start the marking again. 4.053: [GC concurrent-mark-end, 1.9849672 sec] End of the concurrent marking phase and it lasted for 1.9849672 seconds. 4.055: [GC remark 4.055: [GC ref-proc, 0.0000254 secs], 0.0030184 secs] This corresponds to the remark phase which is a stop-the-world phase. It completes the left over marking work (SATB buffers processing) from the previous phase. In this case, this phase took 0.0030184 secs and out of which 0.0000254 secs were spent on Reference processing. 4.088: [GC cleanup 117M->106M(138M), 0.0015198 secs] Cleanup phase which is again a stop-the-world phase. It goes through the marking information of all the regions, computes the live data information of each region, resets the marking data structures and sorts the regions according to their gc-efficiency. In this example, the total heap size is 138M and after the live data counting it was found that the total live data size dropped down from 117M to 106M. 4.090: [GC concurrent-cleanup-start] This concurrent cleanup phase frees up the regions that were found to be empty (didn't contain any live data) during the previous stop-the-world phase. 4.091: [GC concurrent-cleanup-end, 0.0002721] Concurrent cleanup phase took 0.0002721 secs to free up the empty regions. Option -XX:G1PrintRegionLivenessInfo Now, let's look at the output generated with the flag G1PrintRegionLivenessInfo. This is a diagnostic option and gets enabled with -XX:+UnlockDiagnosticVMOptions. G1PrintRegionLivenessInfo prints the live data information of each region during the Cleanup phase of the concurrent-marking cycle. 26.896: [GC cleanup ### PHASE Post-Marking @ 26.896### HEAP committed: 0x02e00000-0x0fe00000 reserved: 0x02e00000-0x12e00000 region-size: 1048576 Cleanup phase of the concurrent-marking cycle started at 26.896 secs from the start of the process and this live data information is being printed after the marking phase. Committed G1 heap ranges from 0x02e00000 to 0x0fe00000 and the total G1 heap reserved by JVM is from 0x02e00000 to 0x12e00000. Each region in the G1 heap is of size 1048576 bytes. ### type address-range used prev-live next-live gc-eff### (bytes) (bytes) (bytes) (bytes/ms) This is the header of the output that tells us about the type of the region, address-range of the region, used space in the region, live bytes in the region with respect to the previous marking cycle, live bytes in the region with respect to the current marking cycle and the GC efficiency of that region. ### FREE 0x02e00000-0x02f00000 0 0 0 0.0 This is a Free region. ### OLD 0x02f00000-0x03000000 1048576 1038592 1038592 0.0 Old region with address-range from 0x02f00000 to 0x03000000. Total used space in the region is 1048576 bytes, live bytes as per the previous marking cycle are 1038592 and live bytes with respect to the current marking cycle are also 1038592. The GC efficiency has been computed as 0. ### EDEN 0x03400000-0x03500000 20992 20992 20992 0.0 This is an Eden region. ### HUMS 0x0ae00000-0x0af00000 1048576 1048576 1048576 0.0### HUMC 0x0af00000-0x0b000000 1048576 1048576 1048576 0.0### HUMC 0x0b000000-0x0b100000 1048576 1048576 1048576 0.0### HUMC 0x0b100000-0x0b200000 1048576 1048576 1048576 0.0### HUMC 0x0b200000-0x0b300000 1048576 1048576 1048576 0.0### HUMC 0x0b300000-0x0b400000 1048576 1048576 1048576 0.0### HUMC 0x0b400000-0x0b500000 1001480 1001480 1001480 0.0 These are the continuous set of regions called Humongous regions for storing a large object. HUMS (Humongous starts) marks the start of the set of humongous regions and HUMC (Humongous continues) tags the subsequent regions of the humongous regions set. ### SURV 0x09300000-0x09400000 16384 16384 16384 0.0 This is a Survivor region. ### SUMMARY capacity: 208.00 MB used: 150.16 MB / 72.19 % prev-live: 149.78 MB / 72.01 % next-live: 142.82 MB / 68.66 % At the end, a summary is printed listing the capacity, the used space and the change in the liveness after the completion of concurrent marking. In this case, G1 heap capacity is 208MB, total used space is 150.16MB which is 72.19% of the total heap size, live data in the previous marking was 149.78MB which was 72.01% of the total heap size and the live data as per the current marking is 142.82MB which is 68.66% of the total heap size. Option -XX:+G1PrintHeapRegions G1PrintHeapRegions option logs the regions related events when regions are committed, allocated into or are reclaimed. COMMIT/UNCOMMIT events G1HR COMMIT [0x6e900000,0x6ea00000]G1HR COMMIT [0x6ea00000,0x6eb00000] Here, the heap is being initialized or expanded and the region (with bottom: 0x6eb00000 and end: 0x6ec00000) is being freshly committed. COMMIT events are always generated in order i.e. the next COMMIT event will always be for the uncommitted region with the lowest address. G1HR UNCOMMIT [0x72700000,0x72800000]G1HR UNCOMMIT [0x72600000,0x72700000] Opposite to COMMIT. The heap got shrunk at the end of a Full GC and the regions are being uncommitted. Like COMMIT, UNCOMMIT events are also generated in order i.e. the next UNCOMMIT event will always be for the committed region with the highest address. GC Cycle events G1HR #StartGC 7G1HR CSET 0x6e900000G1HR REUSE 0x70500000G1HR ALLOC(Old) 0x6f800000G1HR RETIRE 0x6f800000 0x6f821b20G1HR #EndGC 7 This shows start and end of an Evacuation pause. This event is followed by a GC counter tracking both evacuation pauses and Full GCs. Here, this is the 7th GC since the start of the process. G1HR #StartFullGC 17G1HR UNCOMMIT [0x6ed00000,0x6ee00000]G1HR POST-COMPACTION(Old) 0x6e800000 0x6e854f58G1HR #EndFullGC 17 Shows start and end of a Full GC. This event is also followed by the same GC counter as above. This is the 17th GC since the start of the process. ALLOC events G1HR ALLOC(Eden) 0x6e800000 The region with bottom 0x6e800000 just started being used for allocation. In this case it is an Eden region and allocated into by a mutator thread. G1HR ALLOC(StartsH) 0x6ec00000 0x6ed00000G1HR ALLOC(ContinuesH) 0x6ed00000 0x6e000000 Regions being used for the allocation of Humongous object. The object spans over two regions. G1HR ALLOC(SingleH) 0x6f900000 0x6f9eb010 Single region being used for the allocation of Humongous object. G1HR COMMIT [0x6ee00000,0x6ef00000]G1HR COMMIT [0x6ef00000,0x6f000000]G1HR COMMIT [0x6f000000,0x6f100000]G1HR COMMIT [0x6f100000,0x6f200000]G1HR ALLOC(StartsH) 0x6ee00000 0x6ef00000G1HR ALLOC(ContinuesH) 0x6ef00000 0x6f000000G1HR ALLOC(ContinuesH) 0x6f000000 0x6f100000G1HR ALLOC(ContinuesH) 0x6f100000 0x6f102010 Here, Humongous object allocation request could not be satisfied by the free committed regions that existed in the heap, so the heap needed to be expanded. Thus new regions are committed and then allocated into for the Humongous object. G1HR ALLOC(Old) 0x6f800000 Old region started being used for allocation during GC. G1HR ALLOC(Survivor) 0x6fa00000 Region being used for copying old objects into during a GC. Note that Eden and Humongous ALLOC events are generated outside the GC boundaries and Old and Survivor ALLOC events are generated inside the GC boundaries. Other Events G1HR RETIRE 0x6e800000 0x6e87bd98 Retire and stop using the region having bottom 0x6e800000 and top 0x6e87bd98 for allocation. Note that most regions are full when they are retired and we omit those events to reduce the output volume. A region is retired when another region of the same type is allocated or we reach the start or end of a GC(depending on the region). So for Eden regions: For example: 1. ALLOC(Eden) Foo2. ALLOC(Eden) Bar3. StartGC At point 2, Foo has just been retired and it was full. At point 3, Bar was retired and it was full. If they were not full when they were retired, we will have a RETIRE event: 1. ALLOC(Eden) Foo2. RETIRE Foo top3. ALLOC(Eden) Bar4. StartGC G1HR CSET 0x6e900000 Region (bottom: 0x6e900000) is selected for the Collection Set. The region might have been selected for the collection set earlier (i.e. when it was allocated). However, we generate the CSET events for all regions in the CSet at the start of a GC to make sure there's no confusion about which regions are part of the CSet. G1HR POST-COMPACTION(Old) 0x6e800000 0x6e839858 POST-COMPACTION event is generated for each non-empty region in the heap after a full compaction. A full compaction moves objects around, so we don't know what the resulting shape of the heap is (which regions were written to, which were emptied, etc.). To deal with this, we generate a POST-COMPACTION event for each non-empty region with its type (old/humongous) and the heap boundaries. At this point we should only have Old and Humongous regions, as we have collapsed the young generation, so we should not have eden and survivors. POST-COMPACTION events are generated within the Full GC boundary. G1HR CLEANUP 0x6f400000G1HR CLEANUP 0x6f300000G1HR CLEANUP 0x6f200000 These regions were found empty after remark phase of Concurrent Marking and are reclaimed shortly afterwards. G1HR #StartGC 5G1HR CSET 0x6f400000G1HR CSET 0x6e900000G1HR REUSE 0x6f800000 At the end of a GC we retire the old region we are allocating into. Given that its not full, we will carry on allocating into it during the next GC. This is what REUSE means. In the above case 0x6f800000 should have been the last region with an ALLOC(Old) event during the previous GC and should have been retired before the end of the previous GC. G1HR ALLOC-FORCE(Eden) 0x6f800000 A specialization of ALLOC which indicates that we have reached the max desired number of the particular region type (in this case: Eden), but we decided to allocate one more. Currently it's only used for Eden regions when we extend the young generation because we cannot do a GC as the GC-Locker is active. G1HR EVAC-FAILURE 0x6f800000 During a GC, we have failed to evacuate an object from the given region as the heap is full and there is no space left to copy the object. This event is generated within GC boundaries and exactly once for each region from which we failed to evacuate objects. When Heap Regions are reclaimed ? It is also worth mentioning when the heap regions in the G1 heap are reclaimed. All regions that are in the CSet (the ones that appear in CSET events) are reclaimed at the end of a GC. The exception to that are regions with EVAC-FAILURE events. All regions with CLEANUP events are reclaimed. After a Full GC some regions get reclaimed (the ones from which we moved the objects out). But that is not shown explicitly, instead the non-empty regions that are left in the heap are printed out with the POST-COMPACTION events.

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  • Using Stub Objects

    - by user9154181
    Having told the long and winding tale of where stub objects came from and how we use them to build Solaris, I'd like to focus now on the the nuts and bolts of building and using them. The following new features were added to the Solaris link-editor (ld) to support the production and use of stub objects: -z stub This new command line option informs ld that it is to build a stub object rather than a normal object. In this mode, it accepts the same command line arguments as usual, but will quietly ignore any objects and sharable object dependencies. STUB_OBJECT Mapfile Directive In order to build a stub version of an object, its mapfile must specify the STUB_OBJECT directive. When producing a non-stub object, the presence of STUB_OBJECT causes the link-editor to perform extra validation to ensure that the stub and non-stub objects will be compatible. ASSERT Mapfile Directive All data symbols exported from the object must have an ASSERT symbol directive in the mapfile that declares them as data and supplies the size, binding, bss attributes, and symbol aliasing details. When building the stub objects, the information in these ASSERT directives is used to create the data symbols. When building the real object, these ASSERT directives will ensure that the real object matches the linking interface presented by the stub. Although ASSERT was added to the link-editor in order to support stub objects, they are a general purpose feature that can be used independently of stub objects. For instance you might choose to use an ASSERT directive if you have a symbol that must have a specific address in order for the object to operate properly and you want to automatically ensure that this will always be the case. The material presented here is derived from a document I originally wrote during the development effort, which had the dual goals of providing supplemental materials for the stub object PSARC case, and as a set of edits that were eventually applied to the Oracle Solaris Linker and Libraries Manual (LLM). The Solaris 11 LLM contains this information in a more polished form. Stub Objects A stub object is a shared object, built entirely from mapfiles, that supplies the same linking interface as the real object, while containing no code or data. Stub objects cannot be used at runtime. However, an application can be built against a stub object, where the stub object provides the real object name to be used at runtime, and then use the real object at runtime. When building a stub object, the link-editor ignores any object or library files specified on the command line, and these files need not exist in order to build a stub. Since the compilation step can be omitted, and because the link-editor has relatively little work to do, stub objects can be built very quickly. Stub objects can be used to solve a variety of build problems: Speed Modern machines, using a version of make with the ability to parallelize operations, are capable of compiling and linking many objects simultaneously, and doing so offers significant speedups. However, it is typical that a given object will depend on other objects, and that there will be a core set of objects that nearly everything else depends on. It is necessary to impose an ordering that builds each object before any other object that requires it. This ordering creates bottlenecks that reduce the amount of parallelization that is possible and limits the overall speed at which the code can be built. Complexity/Correctness In a large body of code, there can be a large number of dependencies between the various objects. The makefiles or other build descriptions for these objects can become very complex and difficult to understand or maintain. The dependencies can change as the system evolves. This can cause a given set of makefiles to become slightly incorrect over time, leading to race conditions and mysterious rare build failures. Dependency Cycles It might be desirable to organize code as cooperating shared objects, each of which draw on the resources provided by the other. Such cycles cannot be supported in an environment where objects must be built before the objects that use them, even though the runtime linker is fully capable of loading and using such objects if they could be built. Stub shared objects offer an alternative method for building code that sidesteps the above issues. Stub objects can be quickly built for all the shared objects produced by the build. Then, all the real shared objects and executables can be built in parallel, in any order, using the stub objects to stand in for the real objects at link-time. Afterwards, the executables and real shared objects are kept, and the stub shared objects are discarded. Stub objects are built from a mapfile, which must satisfy the following requirements. The mapfile must specify the STUB_OBJECT directive. This directive informs the link-editor that the object can be built as a stub object, and as such causes the link-editor to perform validation and sanity checking intended to guarantee that an object and its stub will always provide identical linking interfaces. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data exported from the object must have an ASSERT symbol attribute in the mapfile to specify the symbol type, size, and bss attributes. In the case where there are multiple symbols that reference the same data, the ASSERT for one of these symbols must specify the TYPE and SIZE attributes, while the others must use the ALIAS attribute to reference this primary symbol. Given such a mapfile, the stub and real versions of the shared object can be built using the same command line for each, adding the '-z stub' option to the link for the stub object, and omiting the option from the link for the real object. To demonstrate these ideas, the following code implements a shared object named idx5, which exports data from a 5 element array of integers, with each element initialized to contain its zero-based array index. This data is available as a global array, via an alternative alias data symbol with weak binding, and via a functional interface. % cat idx5.c int _idx5[5] = { 0, 1, 2, 3, 4 }; #pragma weak idx5 = _idx5 int idx5_func(int index) { if ((index 4)) return (-1); return (_idx5[index]); } A mapfile is required to describe the interface provided by this shared object. % cat mapfile $mapfile_version 2 STUB_OBJECT; SYMBOL_SCOPE { _idx5 { ASSERT { TYPE=data; SIZE=4[5] }; }; idx5 { ASSERT { BINDING=weak; ALIAS=_idx5 }; }; idx5_func; local: *; }; The following main program is used to print all the index values available from the idx5 shared object. % cat main.c #include <stdio.h> extern int _idx5[5], idx5[5], idx5_func(int); int main(int argc, char **argv) { int i; for (i = 0; i The following commands create a stub version of this shared object in a subdirectory named stublib. elfdump is used to verify that the resulting object is a stub. The command used to build the stub differs from that of the real object only in the addition of the -z stub option, and the use of a different output file name. This demonstrates the ease with which stub generation can be added to an existing makefile. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o stublib/libidx5.so.1 -zstub % ln -s libidx5.so.1 stublib/libidx5.so % elfdump -d stublib/libidx5.so | grep STUB [11] FLAGS_1 0x4000000 [ STUB ] The main program can now be built, using the stub object to stand in for the real shared object, and setting a runpath that will find the real object at runtime. However, as we have not yet built the real object, this program cannot yet be run. Attempts to cause the system to load the stub object are rejected, as the runtime linker knows that stub objects lack the actual code and data found in the real object, and cannot execute. % cc main.c -L stublib -R '$ORIGIN/lib' -lidx5 -lc % ./a.out ld.so.1: a.out: fatal: libidx5.so.1: open failed: No such file or directory Killed % LD_PRELOAD=stublib/libidx5.so.1 ./a.out ld.so.1: a.out: fatal: stublib/libidx5.so.1: stub shared object cannot be used at runtime Killed We build the real object using the same command as we used to build the stub, omitting the -z stub option, and writing the results to a different file. % cc -Kpic -G -M mapfile -h libidx5.so.1 idx5.c -o lib/libidx5.so.1 Once the real object has been built in the lib subdirectory, the program can be run. % ./a.out [0] 0 0 0 [1] 1 1 1 [2] 2 2 2 [3] 3 3 3 [4] 4 4 4 Mapfile Changes The version 2 mapfile syntax was extended in a number of places to accommodate stub objects. Conditional Input The version 2 mapfile syntax has the ability conditionalize mapfile input using the $if control directive. As you might imagine, these directives are used frequently with ASSERT directives for data, because a given data symbol will frequently have a different size in 32 or 64-bit code, or on differing hardware such as x86 versus sparc. The link-editor maintains an internal table of names that can be used in the logical expressions evaluated by $if and $elif. At startup, this table is initialized with items that describe the class of object (_ELF32 or _ELF64) and the type of the target machine (_sparc or _x86). We found that there were a small number of cases in the Solaris code base in which we needed to know what kind of object we were producing, so we added the following new predefined items in order to address that need: NameMeaning ...... _ET_DYNshared object _ET_EXECexecutable object _ET_RELrelocatable object ...... STUB_OBJECT Directive The new STUB_OBJECT directive informs the link-editor that the object described by the mapfile can be built as a stub object. STUB_OBJECT; A stub shared object is built entirely from the information in the mapfiles supplied on the command line. When the -z stub option is specified to build a stub object, the presence of the STUB_OBJECT directive in a mapfile is required, and the link-editor uses the information in symbol ASSERT attributes to create global symbols that match those of the real object. When the real object is built, the presence of STUB_OBJECT causes the link-editor to verify that the mapfiles accurately describe the real object interface, and that a stub object built from them will provide the same linking interface as the real object it represents. All function and data symbols that make up the external interface to the object must be explicitly listed in the mapfile. The mapfile must use symbol scope reduction ('*'), to remove any symbols not explicitly listed from the external interface. All global data in the object is required to have an ASSERT attribute that specifies the symbol type and size. If the ASSERT BIND attribute is not present, the link-editor provides a default assertion that the symbol must be GLOBAL. If the ASSERT SH_ATTR attribute is not present, or does not specify that the section is one of BITS or NOBITS, the link-editor provides a default assertion that the associated section is BITS. All data symbols that describe the same address and size are required to have ASSERT ALIAS attributes specified in the mapfile. If aliased symbols are discovered that do not have an ASSERT ALIAS specified, the link fails and no object is produced. These rules ensure that the mapfiles contain a description of the real shared object's linking interface that is sufficient to produce a stub object with a completely compatible linking interface. SYMBOL_SCOPE/SYMBOL_VERSION ASSERT Attribute The SYMBOL_SCOPE and SYMBOL_VERSION mapfile directives were extended with a symbol attribute named ASSERT. The syntax for the ASSERT attribute is as follows: ASSERT { ALIAS = symbol_name; BINDING = symbol_binding; TYPE = symbol_type; SH_ATTR = section_attributes; SIZE = size_value; SIZE = size_value[count]; }; The ASSERT attribute is used to specify the expected characteristics of the symbol. The link-editor compares the symbol characteristics that result from the link to those given by ASSERT attributes. If the real and asserted attributes do not agree, a fatal error is issued and the output object is not created. In normal use, the link editor evaluates the ASSERT attribute when present, but does not require them, or provide default values for them. The presence of the STUB_OBJECT directive in a mapfile alters the interpretation of ASSERT to require them under some circumstances, and to supply default assertions if explicit ones are not present. See the definition of the STUB_OBJECT Directive for the details. When the -z stub command line option is specified to build a stub object, the information provided by ASSERT attributes is used to define the attributes of the global symbols provided by the object. ASSERT accepts the following: ALIAS Name of a previously defined symbol that this symbol is an alias for. An alias symbol has the same type, value, and size as the main symbol. The ALIAS attribute is mutually exclusive to the TYPE, SIZE, and SH_ATTR attributes, and cannot be used with them. When ALIAS is specified, the type, size, and section attributes are obtained from the alias symbol. BIND Specifies an ELF symbol binding, which can be any of the STB_ constants defined in <sys/elf.h>, with the STB_ prefix removed (e.g. GLOBAL, WEAK). TYPE Specifies an ELF symbol type, which can be any of the STT_ constants defined in <sys/elf.h>, with the STT_ prefix removed (e.g. OBJECT, COMMON, FUNC). In addition, for compatibility with other mapfile usage, FUNCTION and DATA can be specified, for STT_FUNC and STT_OBJECT, respectively. TYPE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SH_ATTR Specifies attributes of the section associated with the symbol. The section_attributes that can be specified are given in the following table: Section AttributeMeaning BITSSection is not of type SHT_NOBITS NOBITSSection is of type SHT_NOBITS SH_ATTR is mutually exclusive to ALIAS, and cannot be used in conjunction with it. SIZE Specifies the expected symbol size. SIZE is mutually exclusive to ALIAS, and cannot be used in conjunction with it. The syntax for the size_value argument is as described in the discussion of the SIZE attribute below. SIZE The SIZE symbol attribute existed before support for stub objects was introduced. It is used to set the size attribute of a given symbol. This attribute results in the creation of a symbol definition. Prior to the introduction of the ASSERT SIZE attribute, the value of a SIZE attribute was always numeric. While attempting to apply ASSERT SIZE to the objects in the Solaris ON consolidation, I found that many data symbols have a size based on the natural machine wordsize for the class of object being produced. Variables declared as long, or as a pointer, will be 4 bytes in size in a 32-bit object, and 8 bytes in a 64-bit object. Initially, I employed the conditional $if directive to handle these cases as follows: $if _ELF32 foo { ASSERT { TYPE=data; SIZE=4 } }; bar { ASSERT { TYPE=data; SIZE=20 } }; $elif _ELF64 foo { ASSERT { TYPE=data; SIZE=8 } }; bar { ASSERT { TYPE=data; SIZE=40 } }; $else $error UNKNOWN ELFCLASS $endif I found that the situation occurs frequently enough that this is cumbersome. To simplify this case, I introduced the idea of the addrsize symbolic name, and of a repeat count, which together make it simple to specify machine word scalar or array symbols. Both the SIZE, and ASSERT SIZE attributes support this syntax: The size_value argument can be a numeric value, or it can be the symbolic name addrsize. addrsize represents the size of a machine word capable of holding a memory address. The link-editor substitutes the value 4 for addrsize when building 32-bit objects, and the value 8 when building 64-bit objects. addrsize is useful for representing the size of pointer variables and C variables of type long, as it automatically adjusts for 32 and 64-bit objects without requiring the use of conditional input. The size_value argument can be optionally suffixed with a count value, enclosed in square brackets. If count is present, size_value and count are multiplied together to obtain the final size value. Using this feature, the example above can be written more naturally as: foo { ASSERT { TYPE=data; SIZE=addrsize } }; bar { ASSERT { TYPE=data; SIZE=addrsize[5] } }; Exported Global Data Is Still A Bad Idea As you can see, the additional plumbing added to the Solaris link-editor to support stub objects is minimal. Furthermore, about 90% of that plumbing is dedicated to handling global data. We have long advised against global data exported from shared objects. There are many ways in which global data does not fit well with dynamic linking. Stub objects simply provide one more reason to avoid this practice. It is always better to export all data via a functional interface. You should always hide your data, and make it available to your users via a function that they can call to acquire the address of the data item. However, If you do have to support global data for a stub, perhaps because you are working with an already existing object, it is still easilily done, as shown above. Oracle does not like us to discuss hypothetical new features that don't exist in shipping product, so I'll end this section with a speculation. It might be possible to do more in this area to ease the difficulty of dealing with objects that have global data that the users of the library don't need. Perhaps someday... Conclusions It is easy to create stub objects for most objects. If your library only exports function symbols, all you have to do to build a faithful stub object is to add STUB_OBJECT; and then to use the same link command you're currently using, with the addition of the -z stub option. Happy Stubbing!

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  • Towards Database Continuous Delivery – What Next after Continuous Integration? A Checklist

    - by Ben Rees
    .dbd-banner p{ font-size:0.75em; padding:0 0 10px; margin:0 } .dbd-banner p span{ color:#675C6D; } .dbd-banner p:last-child{ padding:0; } @media ALL and (max-width:640px){ .dbd-banner{ background:#f0f0f0; padding:5px; color:#333; margin-top: 5px; } } -- Database delivery patterns & practices STAGE 4 AUTOMATED DEPLOYMENT If you’ve been fortunate enough to get to the stage where you’ve implemented some sort of continuous integration process for your database updates, then hopefully you’re seeing the benefits of that investment – constant feedback on changes your devs are making, advanced warning of data loss (prior to the production release on Saturday night!), a nice suite of automated tests to check business logic, so you know it’s going to work when it goes live, and so on. But what next? What can you do to improve your delivery process further, moving towards a full continuous delivery process for your database? In this article I describe some of the issues you might need to tackle on the next stage of this journey, and how to plan to overcome those obstacles before they appear. Our Database Delivery Learning Program consists of four stages, really three – source controlling a database, running continuous integration processes, then how to set up automated deployment (the middle stage is split in two – basic and advanced continuous integration, making four stages in total). If you’ve managed to work through the first three of these stages – source control, basic, then advanced CI, then you should have a solid change management process set up where, every time one of your team checks in a change to your database (whether schema or static reference data), this change gets fully tested automatically by your CI server. But this is only part of the story. Great, we know that our updates work, that the upgrade process works, that the upgrade isn’t going to wipe our 4Tb of production data with a single DROP TABLE. But – how do you get this (fully tested) release live? Continuous delivery means being always ready to release your software at any point in time. There’s a significant gap between your latest version being tested, and it being easily releasable. Just a quick note on terminology – there’s a nice piece here from Atlassian on the difference between continuous integration, continuous delivery and continuous deployment. This piece also gives a nice description of the benefits of continuous delivery. These benefits have been summed up by Jez Humble at Thoughtworks as: “Continuous delivery is a set of principles and practices to reduce the cost, time, and risk of delivering incremental changes to users” There’s another really useful piece here on Simple-Talk about the need for continuous delivery and how it applies to the database written by Phil Factor – specifically the extra needs and complexities of implementing a full CD solution for the database (compared to just implementing CD for, say, a web app). So, hopefully you’re convinced of moving on the the next stage! The next step after CI is to get some sort of automated deployment (or “release management”) process set up. But what should I do next? What do I need to plan and think about for getting my automated database deployment process set up? Can’t I just install one of the many release management tools available and hey presto, I’m ready! If only it were that simple. Below I list some of the areas that it’s worth spending a little time on, where a little planning and prep could go a long way. It’s also worth pointing out, that this should really be an evolving process. Depending on your starting point of course, it can be a long journey from your current setup to a full continuous delivery pipeline. If you’ve got a CI mechanism in place, you’re certainly a long way down that path. Nevertheless, we’d recommend evolving your process incrementally. Pages 157 and 129-141 of the book on Continuous Delivery (by Jez Humble and Dave Farley) have some great guidance on building up a pipeline incrementally: http://www.amazon.com/Continuous-Delivery-Deployment-Automation-Addison-Wesley/dp/0321601912 For now, in this post, we’ll look at the following areas for your checklist: You and Your Team Environments The Deployment Process Rollback and Recovery Development Practices You and Your Team It’s a cliché in the DevOps community that “It’s not all about processes and tools, really it’s all about a culture”. As stated in this DevOps report from Puppet Labs: “DevOps processes and tooling contribute to high performance, but these practices alone aren’t enough to achieve organizational success. The most common barriers to DevOps adoption are cultural: lack of manager or team buy-in, or the value of DevOps isn’t understood outside of a specific group”. Like most clichés, there’s truth in there – if you want to set up a database continuous delivery process, you need to get your boss, your department, your company (if relevant) onside. Why? Because it’s an investment with the benefits coming way down the line. But the benefits are huge – for HP, in the book A Practical Approach to Large-Scale Agile Development: How HP Transformed LaserJet FutureSmart Firmware, these are summarized as: -2008 to present: overall development costs reduced by 40% -Number of programs under development increased by 140% -Development costs per program down 78% -Firmware resources now driving innovation increased by a factor of 8 (from 5% working on new features to 40% But what does this mean? It means that, when moving to the next stage, to make that extra investment in automating your deployment process, it helps a lot if everyone is convinced that this is a good thing. That they understand the benefits of automated deployment and are willing to make the effort to transform to a new way of working. Incidentally, if you’re ever struggling to convince someone of the value I’d strongly recommend just buying them a copy of this book – a great read, and a very practical guide to how it can really work at a large org. I’ve spoken to many customers who have implemented database CI who describe their deployment process as “The point where automation breaks down. Up to that point, the CI process runs, untouched by human hand, but as soon as that’s finished we revert to manual.” This deployment process can involve, for example, a DBA manually comparing an environment (say, QA) to production, creating the upgrade scripts, reading through them, checking them against an Excel document emailed to him/her the night before, turning to page 29 in his/her notebook to double-check how replication is switched off and on for deployments, and so on and so on. Painful, error-prone and lengthy. But the point is, if this is something like your deployment process, telling your DBA “We’re changing everything you do and your toolset next week, to automate most of your role – that’s okay isn’t it?” isn’t likely to go down well. There’s some work here to bring him/her onside – to explain what you’re doing, why there will still be control of the deployment process and so on. Or of course, if you’re the DBA looking after this process, you have to do a similar job in reverse. You may have researched and worked out how you’d like to change your methodology to start automating your painful release process, but do the dev team know this? What if they have to start producing different artifacts for you? Will they be happy with this? Worth talking to them, to find out. As well as talking to your DBA/dev team, the other group to get involved before implementation is your manager. And possibly your manager’s manager too. As mentioned, unless there’s buy-in “from the top”, you’re going to hit problems when the implementation starts to get rocky (and what tool/process implementations don’t get rocky?!). You need to have support from someone senior in your organisation – someone you can turn to when you need help with a delayed implementation, lack of resources or lack of progress. Actions: Get your DBA involved (or whoever looks after live deployments) and discuss what you’re planning to do or, if you’re the DBA yourself, get the dev team up-to-speed with your plans, Get your boss involved too and make sure he/she is bought in to the investment. Environments Where are you going to deploy to? And really this question is – what environments do you want set up for your deployment pipeline? Assume everyone has “Production”, but do you have a QA environment? Dedicated development environments for each dev? Proper pre-production? I’ve seen every setup under the sun, and there is often a big difference between “What we want, to do continuous delivery properly” and “What we’re currently stuck with”. Some of these differences are: What we want What we’ve got Each developer with their own dedicated database environment A single shared “development” environment, used by everyone at once An Integration box used to test the integration of all check-ins via the CI process, along with a full suite of unit-tests running on that machine In fact if you have a CI process running, you’re likely to have some sort of integration server running (even if you don’t call it that!). Whether you have a full suite of unit tests running is a different question… Separate QA environment used explicitly for manual testing prior to release “We just test on the dev environments, or maybe pre-production” A proper pre-production (or “staging”) box that matches production as closely as possible Hopefully a pre-production box of some sort. But does it match production closely!? A production environment reproducible from source control A production box which has drifted significantly from anything in source control The big question is – how much time and effort are you going to invest in fixing these issues? In reality this just involves figuring out which new databases you’re going to create and where they’ll be hosted – VMs? Cloud-based? What about size/data issues – what data are you going to include on dev environments? Does it need to be masked to protect access to production data? And often the amount of work here really depends on whether you’re working on a new, greenfield project, or trying to update an existing, brownfield application. There’s a world if difference between starting from scratch with 4 or 5 clean environments (reproducible from source control of course!), and trying to re-purpose and tweak a set of existing databases, with all of their surrounding processes and quirks. But for a proper release management process, ideally you have: Dedicated development databases, An Integration server used for testing continuous integration and running unit tests. [NB: This is the point at which deployments are automatic, without human intervention. Each deployment after this point is a one-click (but human) action], QA – QA engineers use a one-click deployment process to automatically* deploy chosen releases to QA for testing, Pre-production. The environment you use to test the production release process, Production. * A note on the use of the word “automatic” – when carrying out automated deployments this does not mean that the deployment is happening without human intervention (i.e. that something is just deploying over and over again). It means that the process of carrying out the deployment is automatic in that it’s not a person manually running through a checklist or set of actions. The deployment still requires a single-click from a user. Actions: Get your environments set up and ready, Set access permissions appropriately, Make sure everyone understands what the environments will be used for (it’s not a “free-for-all” with all environments to be accessed, played with and changed by development). The Deployment Process As described earlier, most existing database deployment processes are pretty manual. The following is a description of a process we hear very often when we ask customers “How do your database changes get live? How does your manual process work?” Check pre-production matches production (use a schema compare tool, like SQL Compare). Sometimes done by taking a backup from production and restoring in to pre-prod, Again, use a schema compare tool to find the differences between the latest version of the database ready to go live (i.e. what the team have been developing). This generates a script, User (generally, the DBA), reviews the script. This often involves manually checking updates against a spreadsheet or similar, Run the script on pre-production, and check there are no errors (i.e. it upgrades pre-production to what you hoped), If all working, run the script on production.* * this assumes there’s no problem with production drifting away from pre-production in the interim time period (i.e. someone has hacked something in to the production box without going through the proper change management process). This difference could undermine the validity of your pre-production deployment test. Red Gate is currently working on a free tool to detect this problem – sign up here at www.sqllighthouse.com, if you’re interested in testing early versions. There are several variations on this process – some better, some much worse! How do you automate this? In particular, step 3 – surely you can’t automate a DBA checking through a script, that everything is in order!? The key point here is to plan what you want in your new deployment process. There are so many options. At one extreme, pure continuous deployment – whenever a dev checks something in to source control, the CI process runs (including extensive and thorough testing!), before the deployment process keys in and automatically deploys that change to the live box. Not for the faint hearted – and really not something we recommend. At the other extreme, you might be more comfortable with a semi-automated process – the pre-production/production matching process is automated (with an error thrown if these environments don’t match), followed by a manual intervention, allowing for script approval by the DBA. One he/she clicks “Okay, I’m happy for that to go live”, the latter stages automatically take the script through to live. And anything in between of course – and other variations. But we’d strongly recommended sitting down with a whiteboard and your team, and spending a couple of hours mapping out “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” NB: Most of what we’re discussing here is about production deployments. It’s important to note that you will also need to map out a deployment process for earlier environments (for example QA). However, these are likely to be less onerous, and many customers opt for a much more automated process for these boxes. Actions: Sit down with your team and a whiteboard, and draw out the answers to the questions above for your production deployments – “What do we do now?”, “What do we actually want?”, “What will satisfy our needs for continuous delivery, but still maintaining some sort of continuous control over the process?” Repeat for earlier environments (QA and so on). Rollback and Recovery If only every deployment went according to plan! Unfortunately they don’t – and when things go wrong, you need a rollback or recovery plan for what you’re going to do in that situation. Once you move in to a more automated database deployment process, you’re far more likely to be deploying more frequently than before. No longer once every 6 months, maybe now once per week, or even daily. Hence the need for a quick rollback or recovery process becomes paramount, and should be planned for. NB: These are mainly scenarios for handling rollbacks after the transaction has been committed. If a failure is detected during the transaction, the whole transaction can just be rolled back, no problem. There are various options, which we’ll explore in subsequent articles, things like: Immediately restore from backup, Have a pre-tested rollback script (remembering that really this is a “roll-forward” script – there’s not really such a thing as a rollback script for a database!) Have fallback environments – for example, using a blue-green deployment pattern. Different options have pros and cons – some are easier to set up, some require more investment in infrastructure; and of course some work better than others (the key issue with using backups, is loss of the interim transaction data that has been added between the failed deployment and the restore). The best mechanism will be primarily dependent on how your application works and how much you need a cast-iron failsafe mechanism. Actions: Work out an appropriate rollback strategy based on how your application and business works, your appetite for investment and requirements for a completely failsafe process. Development Practices This is perhaps the more difficult area for people to tackle. The process by which you can deploy database updates is actually intrinsically linked with the patterns and practices used to develop that database and linked application. So you need to decide whether you want to implement some changes to the way your developers actually develop the database (particularly schema changes) to make the deployment process easier. A good example is the pattern “Branch by abstraction”. Explained nicely here, by Martin Fowler, this is a process that can be used to make significant database changes (e.g. splitting a table) in a step-wise manner so that you can always roll back, without data loss – by making incremental updates to the database backward compatible. Slides 103-108 of the following slidedeck, from Niek Bartholomeus explain the process: https://speakerdeck.com/niekbartho/orchestration-in-meatspace As these slides show, by making a significant schema change in multiple steps – where each step can be rolled back without any loss of new data – this affords the release team the opportunity to have zero-downtime deployments with considerably less stress (because if an increment goes wrong, they can roll back easily). There are plenty more great patterns that can be implemented – the book Refactoring Databases, by Scott Ambler and Pramod Sadalage is a great read, if this is a direction you want to go in: http://www.amazon.com/Refactoring-Databases-Evolutionary-paperback-Addison-Wesley/dp/0321774515 But the question is – how much of this investment are you willing to make? How often are you making significant schema changes that would require these best practices? Again, there’s a difference here between migrating old projects and starting afresh – with the latter it’s much easier to instigate best practice from the start. Actions: For your business, work out how far down the path you want to go, amending your database development patterns to “best practice”. It’s a trade-off between implementing quality processes, and the necessity to do so (depending on how often you make complex changes). Socialise these changes with your development group. No-one likes having “best practice” changes imposed on them, so good to introduce these ideas and the rationale behind them early.   Summary The next stages of implementing a continuous delivery pipeline for your database changes (once you have CI up and running) require a little pre-planning, if you want to get the most out of the work, and for the implementation to go smoothly. We’ve covered some of the checklist of areas to consider – mainly in the areas of “Getting the team ready for the changes that are coming” and “Planning our your pipeline, environments, patterns and practices for development”, though there will be more detail, depending on where you’re coming from – and where you want to get to. This article is part of our database delivery patterns & practices series on Simple Talk. Find more articles for version control, automated testing, continuous integration & deployment.

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  • Using the jQuery UI Library in a MVC 3 Application to Build a Dialog Form

    - by ChrisD
    Using a simulated dialog window is a nice way to handle inline data editing. The jQuery UI has a UI widget for a dialog window that makes it easy to get up and running with it in your application. With the release of ASP.NET MVC 3, Microsoft included the jQuery UI scripts and files in the MVC 3 project templates for Visual Studio. With the release of the MVC 3 Tools Update, Microsoft implemented the inclusion of those with NuGet as packages. That means we can get up and running using the latest version of the jQuery UI with minimal effort. To the code! Another that might interested you about JQuery Mobile and ASP.NET MVC 3 with C#. If you are starting with a new MVC 3 application and have the Tools Update then you are a NuGet update and a <link> and <script> tag away from adding the jQuery UI to your project. If you are using an existing MVC project you can still get the jQuery UI library added to your project via NuGet and then add the link and script tags. Assuming that you have pulled down the latest version (at the time of this publish it was 1.8.13) you can add the following link and script tags to your <head> tag: < link href = "@Url.Content(" ~ / Content / themes / base / jquery . ui . all . css ")" rel = "Stylesheet" type = "text/css" /> < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > The jQuery UI library relies upon the CSS scripts and some image files to handle rendering of its widgets (you can choose a different theme or role your own if you like). Adding these to the stock _Layout.cshtml file results in the following markup: <!DOCTYPE html> < html > < head >     < meta charset = "utf-8" />     < title > @ViewBag.Title </ title >     < link href = "@Url.Content(" ~ / Content / Site . css ")" rel = "stylesheet" type = "text/css" />     <link href="@Url.Content("~/Content/themes/base/jquery.ui.all.css")" rel="Stylesheet" type="text/css" />     <script src="@Url.Content("~/Scripts/jquery-1.5.1.min.js")" type="text/javascript"></script>     <script src="@Url.Content("~/Scripts/modernizr-1.7.min . js ")" type = "text/javascript" ></ script >     < script src = "@Url.Content(" ~ / Scripts / jquery-ui-1 . 8 . 13 . min . js ")" type = "text/javascript" ></ script > </ head > < body >     @RenderBody() </ body > </ html > Our example will involve building a list of notes with an id, title and description. Each note can be edited and new notes can be added. The user will never have to leave the single page of notes to manage the note data. The add and edit forms will be delivered in a jQuery UI dialog widget and the note list content will get reloaded via an AJAX call after each change to the list. To begin, we need to craft a model and a data management class. We will do this so we can simulate data storage and get a feel for the workflow of the user experience. The first class named Note will have properties to represent our data model. namespace Website . Models {     public class Note     {         public int Id { get ; set ; }         public string Title { get ; set ; }         public string Body { get ; set ; }     } } The second class named NoteManager will be used to set up our simulated data storage and provide methods for querying and updating the data. We will take a look at the class content as a whole and then walk through each method after. using System . Collections . ObjectModel ; using System . Linq ; using System . Web ; namespace Website . Models {     public class NoteManager     {         public Collection < Note > Notes         {             get             {                 if ( HttpRuntime . Cache [ "Notes" ] == null )                     this . loadInitialData ();                 return ( Collection < Note >) HttpRuntime . Cache [ "Notes" ];             }         }         private void loadInitialData ()         {             var notes = new Collection < Note >();             notes . Add ( new Note                           {                               Id = 1 ,                               Title = "Set DVR for Sunday" ,                               Body = "Don't forget to record Game of Thrones!"                           });             notes . Add ( new Note                           {                               Id = 2 ,                               Title = "Read MVC article" ,                               Body = "Check out the new iwantmymvc.com post"                           });             notes . Add ( new Note                           {                               Id = 3 ,                               Title = "Pick up kid" ,                               Body = "Daughter out of school at 1:30pm on Thursday. Don't forget!"                           });             notes . Add ( new Note                           {                               Id = 4 ,                               Title = "Paint" ,                               Body = "Finish the 2nd coat in the bathroom"                           });             HttpRuntime . Cache [ "Notes" ] = notes ;         }         public Collection < Note > GetAll ()         {             return Notes ;         }         public Note GetById ( int id )         {             return Notes . Where ( i => i . Id == id ). FirstOrDefault ();         }         public int Save ( Note item )         {             if ( item . Id <= 0 )                 return saveAsNew ( item );             var existingNote = Notes . Where ( i => i . Id == item . Id ). FirstOrDefault ();             existingNote . Title = item . Title ;             existingNote . Body = item . Body ;             return existingNote . Id ;         }         private int saveAsNew ( Note item )         {             item . Id = Notes . Count + 1 ;             Notes . Add ( item );             return item . Id ;         }     } } The class has a property named Notes that is read only and handles instantiating a collection of Note objects in the runtime cache if it doesn't exist, and then returns the collection from the cache. This property is there to give us a simulated storage so that we didn't have to add a full blown database (beyond the scope of this post). The private method loadInitialData handles pre-filling the collection of Note objects with some initial data and stuffs them into the cache. Both of these chunks of code would be refactored out with a move to a real means of data storage. The GetAll and GetById methods access our simulated data storage to return all of our notes or a specific note by id. The Save method takes in a Note object, checks to see if it has an Id less than or equal to zero (we assume that an Id that is not greater than zero represents a note that is new) and if so, calls the private method saveAsNew . If the Note item sent in has an Id , the code finds that Note in the simulated storage, updates the Title and Description , and returns the Id value. The saveAsNew method sets the Id , adds it to the simulated storage, and returns the Id value. The increment of the Id is simulated here by getting the current count of the note collection and adding 1 to it. The setting of the Id is the only other chunk of code that would be refactored out when moving to a different data storage approach. With our model and data manager code in place we can turn our attention to the controller and views. We can do all of our work in a single controller. If we use a HomeController , we can add an action method named Index that will return our main view. An action method named List will get all of our Note objects from our manager and return a partial view. We will use some jQuery to make an AJAX call to that action method and update our main view with the partial view content returned. Since the jQuery AJAX call will cache the call to the content in Internet Explorer by default (a setting in jQuery), we will decorate the List, Create and Edit action methods with the OutputCache attribute and a duration of 0. This will send the no-cache flag back in the header of the content to the browser and jQuery will pick that up and not cache the AJAX call. The Create action method instantiates a new Note model object and returns a partial view, specifying the NoteForm.cshtml view file and passing in the model. The NoteForm view is used for the add and edit functionality. The Edit action method takes in the Id of the note to be edited, loads the Note model object based on that Id , and does the same return of the partial view as the Create method. The Save method takes in the posted Note object and sends it to the manager to save. It is decorated with the HttpPost attribute to ensure that it will only be available via a POST. It returns a Json object with a property named Success that can be used by the UX to verify everything went well (we won't use that in our example). Both the add and edit actions in the UX will post to the Save action method, allowing us to reduce the amount of unique jQuery we need to write in our view. The contents of the HomeController.cs file: using System . Web . Mvc ; using Website . Models ; namespace Website . Controllers {     public class HomeController : Controller     {         public ActionResult Index ()         {             return View ();         }         [ OutputCache ( Duration = 0 )]         public ActionResult List ()         {             var manager = new NoteManager ();             var model = manager . GetAll ();             return PartialView ( model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Create ()         {             var model = new Note ();             return PartialView ( "NoteForm" , model );         }         [ OutputCache ( Duration = 0 )]         public ActionResult Edit ( int id )         {             var manager = new NoteManager ();             var model = manager . GetById ( id );             return PartialView ( "NoteForm" , model );         }         [ HttpPost ]         public JsonResult Save ( Note note )         {             var manager = new NoteManager ();             var noteId = manager . Save ( note );             return Json ( new { Success = noteId > 0 });         }     } } The view for the note form, NoteForm.cshtml , looks like so: @model Website . Models . Note @using ( Html . BeginForm ( "Save" , "Home" , FormMethod . Post , new { id = "NoteForm" })) { @Html . Hidden ( "Id" ) < label class = "Title" >     < span > Title < /span><br / >     @Html . TextBox ( "Title" ) < /label> <label class="Body">     <span>Body</ span >< br />     @Html . TextArea ( "Body" ) < /label> } It is a strongly typed view for our Note model class. We give the <form> element an id attribute so that we can reference it via jQuery. The <label> and <span> tags give our UX some structure that we can style with some CSS. The List.cshtml view is used to render out a <ul> element with all of our notes. @model IEnumerable < Website . Models . Note > < ul class = "NotesList" >     @foreach ( var note in Model )     {     < li >         @note . Title < br />         @note . Body < br />         < span class = "EditLink ButtonLink" noteid = "@note.Id" > Edit < /span>     </ li >     } < /ul> This view is strongly typed as well. It includes a <span> tag that we will use as an edit button. We add a custom attribute named noteid to the <span> tag that we can use in our jQuery to identify the Id of the note object we want to edit. The view, Index.cshtml , contains a bit of html block structure and all of our jQuery logic code. @ {     ViewBag . Title = "Index" ; } < h2 > Notes < /h2> <div id="NoteListBlock"></ div > < span class = "AddLink ButtonLink" > Add New Note < /span> <div id="NoteDialog" title="" class="Hidden"></ div > < script type = "text/javascript" >     $ ( function () {         $ ( "#NoteDialog" ). dialog ({             autoOpen : false , width : 400 , height : 330 , modal : true ,             buttons : {                 "Save" : function () {                     $ . post ( "/Home/Save" ,                         $ ( "#NoteForm" ). serialize (),                         function () {                             $ ( "#NoteDialog" ). dialog ( "close" );                             LoadList ();                         });                 },                 Cancel : function () { $ ( this ). dialog ( "close" ); }             }         });         $ ( ".EditLink" ). live ( "click" , function () {             var id = $ ( this ). attr ( "noteid" );             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Edit Note" )                 . load ( "/Home/Edit/" + id , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         $ ( ".AddLink" ). click ( function () {             $ ( "#NoteDialog" ). html ( "" )                 . dialog ( "option" , "title" , "Add Note" )                 . load ( "/Home/Create" , function () { $ ( "#NoteDialog" ). dialog ( "open" ); });         });         LoadList ();     });     function LoadList () {         $ ( "#NoteListBlock" ). load ( "/Home/List" );     } < /script> The <div> tag with the id attribute of "NoteListBlock" is used as a container target for the load of the partial view content of our List action method. It starts out empty and will get loaded with content via jQuery once the DOM is loaded. The <div> tag with the id attribute of "NoteDialog" is the element for our dialog widget. The jQuery UI library will use the title attribute for the text in the dialog widget top header bar. We start out with it empty here and will dynamically change the text via jQuery based on the request to either add or edit a note. This <div> tag is given a CSS class named "Hidden" that will set the display:none style on the element. Since our call to the jQuery UI method to make the element a dialog widget will occur in the jQuery document ready code block, the end user will see the <div> element rendered in their browser as the page renders and then it will hide after that jQuery call. Adding the display:hidden to the <div> element via CSS will ensure that it is never rendered until the user triggers the request to open the dialog. The jQuery document load block contains the setup for the dialog node, click event bindings for the edit and add links, and a call to a JavaScript function called LoadList that handles the AJAX call to the List action method. The .dialog() method is called on the "NoteDialog" <div> element and the options are set for the dialog widget. The buttons option defines 2 buttons and their click actions. The first is the "Save" button (the text in quotations is used as the text for the button) that will do an AJAX post to our Save action method and send the serialized form data from the note form (targeted with the id attribute "NoteForm"). Upon completion it will close the dialog widget and call the LoadList to update the UX without a redirect. The "Cancel" button simply closes the dialog widget. The .live() method handles binding a function to the "click" event on all elements with the CSS class named EditLink . We use the .live() method because it will catch and bind our function to elements even as the DOM changes. Since we will be constantly changing the note list as we add and edit we want to ensure that the edit links get wired up with click events. The function for the click event on the edit links gets the noteid attribute and stores it in a local variable. Then it clears out the HTML in the dialog element (to ensure a fresh start), calls the .dialog() method and sets the "title" option (this sets the title attribute value), and then calls the .load() AJAX method to hit our Edit action method and inject the returned content into the "NoteDialog" <div> element. Once the .load() method is complete it opens the dialog widget. The click event binding for the add link is similar to the edit, only we don't need to get the id value and we load the Create action method. This binding is done via the .click() method because it will only be bound on the initial load of the page. The add button will always exist. Finally, we toss in some CSS in the Content/Site.css file to style our form and the add/edit links. . ButtonLink { color : Blue ; cursor : pointer ; } . ButtonLink : hover { text - decoration : underline ; } . Hidden { display : none ; } #NoteForm label { display:block; margin-bottom:6px; } #NoteForm label > span { font-weight:bold; } #NoteForm input[type=text] { width:350px; } #NoteForm textarea { width:350px; height:80px; } With all of our code in place we can do an F5 and see our list of notes: If we click on an edit link we will get the dialog widget with the correct note data loaded: And if we click on the add new note link we will get the dialog widget with the empty form: The end result of our solution tree for our sample:

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  • Partner Blog Series: PwC Perspectives - The Gotchas, The Do's and Don'ts for IDM Implementations

    - by Tanu Sood
    Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:12.0pt; mso-para-margin-left:0in; line-height:12.0pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Arial","sans-serif"; mso-ascii-font-family:Arial; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableMediumList1Accent6 {mso-style-name:"Medium List 1 - Accent 6"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:65; mso-style-unhide:no; border-top:solid #E0301E 1.0pt; 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mso-table-condition:last-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; color:#968C6D; mso-themecolor:text2; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6FirstCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-column; mso-style-priority:65; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6LastCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6OddColumn {mso-style-name:"Medium List 1 - Accent 6"; 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mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} table.MsoTableMediumList1Accent6 {mso-style-name:"Medium List 1 - Accent 6"; mso-tstyle-rowband-size:1; mso-tstyle-colband-size:1; mso-style-priority:65; mso-style-unhide:no; border-top:solid #E0301E 1.0pt; mso-border-top-themecolor:accent6; border-left:none; border-bottom:solid #E0301E 1.0pt; mso-border-bottom-themecolor:accent6; border-right:none; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Georgia","serif"; color:black; mso-themecolor:text1; mso-ansi-language:EN-GB;} table.MsoTableMediumList1Accent6FirstRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:cell-none; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; font-family:"Arial Narrow","sans-serif"; mso-ascii-font-family:Georgia; mso-ascii-theme-font:major-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:major-fareast; mso-hansi-font-family:Georgia; mso-hansi-theme-font:major-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:major-bidi;} table.MsoTableMediumList1Accent6LastRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; color:#968C6D; mso-themecolor:text2; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6FirstCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:first-column; mso-style-priority:65; mso-style-unhide:no; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6LastCol {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:last-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-border-top:1.0pt solid #E0301E; mso-tstyle-border-top-themecolor:accent6; mso-tstyle-border-bottom:1.0pt solid #E0301E; mso-tstyle-border-bottom-themecolor:accent6; mso-ansi-font-weight:bold; mso-bidi-font-weight:bold;} table.MsoTableMediumList1Accent6OddColumn {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-column; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} table.MsoTableMediumList1Accent6OddRow {mso-style-name:"Medium List 1 - Accent 6"; mso-table-condition:odd-row; mso-style-priority:65; mso-style-unhide:no; mso-tstyle-shading:#F7CBC7; mso-tstyle-shading-themecolor:accent6; mso-tstyle-shading-themetint:63;} It is generally accepted among business communities that technology by itself is not a silver bullet to all problems, but when it is combined with leading practices, strategy, careful planning and execution, it can create a recipe for success. This post attempts to highlight some of the best practices along with dos & don’ts that our practice has accumulated over the years in the identity & access management space in general, and also in the context of R2, in particular. Best Practices The following section illustrates the leading practices in “How” to plan, implement and sustain a successful OIM deployment, based on our collective experience. Planning is critical, but often overlooked A common approach to planning an IAM program that we identify with our clients is the three step process involving a current state assessment, a future state roadmap and an executable strategy to get there. It is extremely beneficial for clients to assess their current IAM state, perform gap analysis, document the recommended controls to address the gaps, align future state roadmap to business initiatives and get buy in from all stakeholders involved to improve the chances of success. When designing an enterprise-wide solution, the scalability of the technology must accommodate the future growth of the enterprise and the projected identity transactions over several years. Aligning the implementation schedule of OIM to related information technology projects increases the chances of success. As a baseline, it is recommended to match hardware specifications to the sizing guide for R2 published by Oracle. Adherence to this will help ensure that the hardware used to support OIM will not become a bottleneck as the adoption of new services increases. If your Organization has numerous connected applications that rely on reconciliation to synchronize the access data into OIM, consider hosting dedicated instances to handle reconciliation. Finally, ensure the use of clustered environment for development and have at least three total environments to help facilitate a controlled migration to production. If your Organization is planning to implement role based access control, we recommend performing a role mining exercise and consolidate your enterprise roles to keep them manageable. In addition, many Organizations have multiple approval flows to control access to critical roles, applications and entitlements. If your Organization falls into this category, we highly recommend that you limit the number of approval workflows to a small set. Most Organizations have operations managed across data centers with backend database synchronization, if your Organization falls into this category, ensure that the overall latency between the datacenters when replicating the databases is less than ten milliseconds to ensure that there are no front office performance impacts. Ingredients for a successful implementation During the development phase of your project, there are a number of guidelines that can be followed to help increase the chances for success. Most implementations cannot be completed without the use of customizations. If your implementation requires this, it’s a good practice to perform code reviews to help ensure quality and reduce code bottlenecks related to performance. We have observed at our clients that the development process works best when team members adhere to coding leading practices. Plan for time to correct coding defects and ensure developers are empowered to report their own bugs for maximum transparency. Many organizations struggle with defining a consistent approach to managing logs. This is particularly important due to the amount of information that can be logged by OIM. We recommend Oracle Diagnostics Logging (ODL) as an alternative to be used for logging. ODL allows log files to be formatted in XML for easy parsing and does not require a server restart when the log levels are changed during troubleshooting. Testing is a vital part of any large project, and an OIM R2 implementation is no exception. We suggest that at least one lower environment should use production-like data and connectors. Configurations should match as closely as possible. For example, use secure channels between OIM and target platforms in pre-production environments to test the configurations, the migration processes of certificates, and the additional overhead that encryption could impose. Finally, we ask our clients to perform database backups regularly and before any major change event, such as a patch or migration between environments. In the lowest environments, we recommend to have at least a weekly backup in order to prevent significant loss of time and effort. Similarly, if your organization is using virtual machines for one or more of the environments, it is recommended to take frequent snapshots so that rollbacks can occur in the event of improper configuration. Operate & sustain the solution to derive maximum benefits When migrating OIM R2 to production, it is important to perform certain activities that will help achieve a smoother transition. At our clients, we have seen that splitting the OIM tables into their own tablespaces by categories (physical tables, indexes, etc.) can help manage database growth effectively. If we notice that a client hasn’t enabled the Oracle-recommended indexing in the applicable database, we strongly suggest doing so to improve performance. Additionally, we work with our clients to make sure that the audit level is set to fit the organization’s auditing needs and sometimes even allocate UPA tables and indexes into their own table-space for better maintenance. Finally, many of our clients have set up schedules for reconciliation tables to be archived at regular intervals in order to keep the size of the database(s) reasonable and result in optimal database performance. For our clients that anticipate availability issues with target applications, we strongly encourage the use of the offline provisioning capabilities of OIM R2. This reduces the provisioning process for a given target application dependency on target availability and help avoid broken workflows. To account for this and other abnormalities, we also advocate that OIM’s monitoring controls be configured to alert administrators on any abnormal situations. Within OIM R2, we have begun advising our clients to utilize the ‘profile’ feature to encapsulate multiple commonly requested accounts, roles, and/or entitlements into a single item. By setting up a number of profiles that can be searched for and used, users will spend less time performing the same exact steps for common tasks. We advise our clients to follow the Oracle recommended guides for database and application server tuning which provides a good baseline configuration. It offers guidance on database connection pools, connection timeouts, user interface threads and proper handling of adapters/plug-ins. All of these can be important configurations that will allow faster provisioning and web page response times. Many of our clients have begun to recognize the value of data mining and a remediation process during the initial phases of an implementation (to help ensure high quality data gets loaded) and beyond (to support ongoing maintenance and business-as-usual processes). A successful program always begins with identifying the data elements and assigning a classification level based on criticality, risk, and availability. It should finish by following through with a remediation process. Dos & Don’ts Here are the most common dos and don'ts that we socialize with our clients, derived from our experience implementing the solution. Dos Don’ts Scope the project into phases with realistic goals. Look for quick wins to show success and value to the stake holders. Avoid “boiling the ocean” and trying to integrate all enterprise applications in the first phase. Establish an enterprise ID (universal unique ID across the enterprise) earlier in the program. Avoid major UI customizations that require code changes. Have a plan in place to patch during the project, which helps alleviate any major issues or roadblocks (product and database). Avoid publishing all the target entitlements if you don't anticipate their usage during access request. Assess your current state and prepare a roadmap to address your operations, tactical and strategic goals, align it with your business priorities. Avoid integrating non-production environments with your production target systems. Defer complex integrations to the later phases and take advantage of lessons learned from previous phases Avoid creating multiple accounts for the same user on the same system, if there is an opportunity to do so. Have an identity and access data quality initiative built into your plan to identify and remediate data related issues early on. Avoid creating complex approval workflows that would negative impact productivity and SLAs. Identify the owner of the identity systems with fair IdM knowledge and empower them with authority to make product related decisions. This will help ensure overcome any design hurdles. Avoid creating complex designs that are not sustainable long term and would need major overhaul during upgrades. Shadow your internal or external consulting resources during the implementation to build the necessary product skills needed to operate and sustain the solution. Avoid treating IAM as a point solution and have appropriate level of communication and training plan for the IT and business users alike. Conclusion In our experience, Identity programs will struggle with scope, proper resourcing, and more. We suggest that companies consider the suggestions discussed in this post and leverage them to help enable their identity and access program. This concludes PwC blog series on R2 for the month and we sincerely hope that the information we have shared thus far has been beneficial. For more information or if you have questions, you can reach out to Rex Thexton, Senior Managing Director, PwC and or Dharma Padala, Director, PwC. We look forward to hearing from you. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:12.0pt; mso-para-margin-left:0in; line-height:12.0pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Arial","sans-serif"; mso-ascii-font-family:Arial; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Arial; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Meet the Writers: Dharma Padala is a Director in the Advisory Security practice within PwC.  He has been implementing medium to large scale Identity Management solutions across multiple industries including utility, health care, entertainment, retail and financial sectors.   Dharma has 14 years of experience in delivering IT solutions out of which he has been implementing Identity Management solutions for the past 8 years. Praveen Krishna is a Manager in the Advisory Security practice within PwC.  Over the last decade Praveen has helped clients plan, architect and implement Oracle identity solutions across diverse industries.  His experience includes delivering security across diverse topics like network, infrastructure, application and data where he brings a holistic point of view to problem solving. Scott MacDonald is a Director in the Advisory Security practice within PwC.  He has consulted for several clients across multiple industries including financial services, health care, automotive and retail.   Scott has 10 years of experience in delivering Identity Management solutions. John Misczak is a member of the Advisory Security practice within PwC.  He has experience implementing multiple Identity and Access Management solutions, specializing in Oracle Identity Manager and Business Process Engineering Language (BPEL).

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  • Generating moderately interesting images

    - by Williham Totland
    Abstract: Can you propose a mathematical-ish algorithm over a plane of pixels that will generate a moderately interesting image, preferably one that on the whole resembles something? The story thus far: Once upon a time I decided in an effort to reduce cycle waste on my (admittedly too) numerous computers, and set out to generate images in a moderately interesting fashion; using a PRNG and some clever math to create images that would, on the whole, resemble something. Or at least, that was the plan. As it turns out, clever math requires being a clever mathematician; this I am not. At some length I arrived at a method that preferred straight lines (as these are generally the components of which our world is made), perhaps too strongly. The result is mildly interesting; resembling, perhaps, city grids as such: Now for the question proper: Given the source code of this little program; can you improve upon it and propose a method that gives somewhat more interesting results? (e.g. not city grids, but perhaps faces, animals, geography, what have you) This is also meant as a sort of challenge; I suppose and as such I've set down some completely arbitrary and equally optional rules: The comments in the code says it all really. Suggestions and "solutions" should edit the algorithm itself, not the surrounding framework, except as for to fix errors that prevents the sample from compiling. The code should compile cleanly with a standard issue C compiler. (If the example provided doesn't, oops! Tell me, and I'll fix. :) The method should, though again, this is optional, not need to elicit help from your friendly neighborhood math library. Solutions should probably be deliverable by simply yanking out whatever is between the snip lines (the ones that say you should not edit above and below, respectively), with a statement to the effect of what you need to add to the preamble in particular. The code requires a C compiler and libpng to build; I'm not entirely confident that the MinGW compiler provides the necessities, but I would be surprised if it didn't. For Debian you'll want the libpng-dev package, and for Mac OS X you'll want the XCode tools.. The source code can be downloaded here. Warning: Massive code splurge incoming! // compile with gcc -o imggen -lpng imggen.c // optionally with -DITERATIONS=x, where x is an appropriate integer // If you're on a Mac or using MinGW, you may have to fiddle with the linker flags to find the library and includes. #include <stdio.h> #include <stdlib.h> #include <png.h> #ifdef ITERATIONS #define REPEAT #endif // ITERATIONS // YOU MAY CHANGE THE FOLLOWING DEFINES #define WIDTH 320 #define HEIGHT 240 // YOU MAY REPLACE THE FOLLOWING DEFINES AS APPROPRIATE #define INK 16384 void writePNG (png_bytepp imageBuffer, png_uint_32 width, png_uint_32 height, int iteration) { char *fname; asprintf(&fname, "out.%d.png", iteration); FILE *fp = fopen(fname, "wb"); if (!fp) return; png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); png_infop info_ptr = png_create_info_struct(png_ptr); png_init_io(png_ptr, fp); png_set_filter(png_ptr, PNG_FILTER_TYPE_DEFAULT, PNG_FILTER_NONE); png_set_compression_level(png_ptr, Z_BEST_COMPRESSION); png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); png_set_rows(png_ptr, info_ptr, imageBuffer); png_set_invert_mono(png_ptr); /// YOU MAY COMMENT OUT THIS LINE png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, NULL); png_destroy_write_struct(&png_ptr, &info_ptr); fclose(fp); free(fname); } int main (int argc, const char * argv[]) { png_uint_32 height = HEIGHT, width = WIDTH; int iteration = 1; #ifdef REPEAT for (iteration = 1; iteration <= ITERATIONS; iteration++) { #endif // REPEAT png_bytepp imageBuffer = malloc(sizeof(png_bytep) * height); for (png_uint_32 i = 0; i < height; i++) { imageBuffer[i] = malloc(sizeof(png_byte) * width); for (png_uint_32 j = 0; j < width; j++) { imageBuffer[i][j] = 0; } } /// CUT ACROSS THE DASHED LINES /// ------------------------------------------- /// NO EDITING ABOVE THIS LINE; EXCEPT AS NOTED int ink = INK; int x = rand() % width, y = rand() % height; int xdir = (rand() % 2)?1:-1; int ydir = (rand() % 2)?1:-1; while (ink) { imageBuffer[y][x] = 255; --ink; xdir += (rand() % 2)?(1):(-1); ydir += (rand() % 2)?(1):(-1); if (ydir > 0) { ++y; } else if (ydir < 0) { --y; } if (xdir > 0) { ++x; } else if (xdir < 0) { --x; } if (x == -1 || y == -1 || x == width || y == height || x == y && x == 0) { x = rand() % width; y = rand() % height; xdir = (rand() % 2)?1:-1; ydir = (rand() % 2)?1:-1; } } /// NO EDITING BELOW THIS LINE /// ------------------------------------------- writePNG(imageBuffer, width, height, iteration); for (png_uint_32 i = 0; i < height; i++) { free(imageBuffer[i]); } free(imageBuffer); #ifdef REPEAT } #endif // REPEAT return 0; } Note: While this question doesn't strictly speaking seem "answerable" as such; I still believe that it can give rise to some manner of "right" answer. Maybe. Happy hunting.

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  • Need guidance on a Google Map application that has to show 250 000 polylines.

    - by lucian.jp
    I am looking for advice for an application I am developing that uses Google Map. Summary: A user has a list of criteria for searching a street segment that fulfills the criteria. The street segments will be colored with 3 colors for showing those below average, average and over average. Then the user clicks on the street segment to see an information window showing the properties of that specific segment hiding those not selected until he/she closes the window and other polyline becomes visible again. This looks quite like the Monopoly City Streets game Hasbro made some month ago the difference being I do not use Flash, I can’t use Open Street Map because it doesn’t list street segment (if it does the IDs won’t be the same anyway) and I do not have to show Google sketch building over. Information: I have a database of street segments with IDs, polyline points and centroid. The database has 6,000,000 street segment records in it. To narrow the generated data a bit we focus on city. The largest city we must show has 250,000 street segments. This means 250,000 line segment polyline to show. Our longest polyline uses 9600 characters which is stored in two 8000 varchar columns in SQL Server 2008. We need to use the API v3 because it is faster than the API v2 and the application will be ported to iPhone. For now it's an ASP.NET 3.5 with SQl Server 2008 application. Performance is a priority. Problems: Most of the demo projects that do this are made with API v2. So besides tutorial on the Google API v3 reference page I have nothing to compare performance or technology use to achieve my goal. There is no available .NET wrapper for the API v3 yet. Generating a 250,000 line segment polyline creates a heavy file which takes time to transfer and parse. (I have found a demo of one polyline of 390,000 points. I think the encoder would be far less efficient with more polylines with less points since there will be less rounding.) Since streets segments are shown based on criteria, polylines must be dynamically created and cache can't be used. Some thoughts: KML/KMZ: Pros: Since it is a standard we can easily load Bing maps, Yahoo! maps, Google maps, Google Earth, with the same KML file. The data generation would be the same. Cons: LineString in KML cannot be encoded polyline like the Google map API can handle. So it would probably be bigger and slower to display. Zipping the file at the size it will take more processing time and require the client side to uncompress the data and I am not quite sure with 250,000 data how an iPhone would handle this and how a server would handle 40 users browsing at the same time. JavaScript file: Pros: JavaScript file can have encoded polyline and would significantly reduce the file to transfer. Cons: Have to create my own stripped version of API v3 to add overlays, create polyline, etc. It is more complex than just create a KML file and point to the source. GeoRSS: This option isn't adapted for my needs I think, but I could be wrong. MapServer: I saw some post suggesting using MapServer to generate overlays. Not quite sure for the connection with our database and the performance it would give. Plus it requires a plugin for generating KML. It seems to me that it wouldn't allow me to do better than creating my own KML or JavaScript file. Maintenance would be simpler without. Monopoly City Streets: The game is now over, but for those who know what I am talking about Monopoly City Streets was showing at max zoom level only the streets that the centroid was inside the Bounds of the window. Moving the map was sending request to the server for the new streets to show. While I think this was ingenious, I have no idea how to implement something similar. The only thing I thought about was to compare if the long was inside the bound of map area X and same with Y. While this could improve performance significantly at high zoom level, this would give nothing when showing a whole city. Clustering: While cluster is awesome for marker, it seems we cannot cluster polylines. I would have liked something like MarkerClusterer for polylines and be able to cluster by my 3 polyline colors. This will probably stay as a “would have been freaking awesome but forget it”. Arrow: I will have in a future version to show a direction for the polyline and will have to show an arrow at the centroid. Loading an image or marker will only double my data so creating a custom overlay will probably be my only option. I have found that demo for something similar I would like to achieve. Unfortunately, the demo is very slow, but I only wish to show 1 arrow per polyline and not multiple like the demo. This functionality will depend on the format of data since I don't think KML support custom overlays. Criteria: While the application is done with ASP.NET 3.5, the port to the iPhone won't use the web to show the application and be limited in screen size for selecting the criteria. This is why I was more orienting on a service or page generating the file based on criteria passed in parameters. The service would than generate the file I need to display the polylines on the map. I could also create an aspx page that does this. The aspx page is more documented than the service way. There should be a reason. Questions: Should I create a web service to returns the street segments file or create an aspx page that return the file? Should I create a JavaScript file with encoded polyline or a KML with longitude/latitude based on the fact that maximum longitude/latitude polyline have 9600 characters and I have to render maximum 250,000 line segment polyline. Or should I go with a MapServer that generate the overlay? Will I be able to display simple arrow on the polyline on the next version. In case of KML generation is it faster to create the file with XDocument, XmlDocument, XmlWriter and this manually or just serialize the street segment in the stream? This is more a brainstorming Stack Overflow question than an actual code problem. Any answer helping narrow the possibilities is as good as someone having all the knowledge to point me out a better choice.

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  • Increase efficiency of a loop with jQuery

    - by Pez Cuckow
    I have a game coded in jQuery where bots are moved around the screen. The below code is a loop that runs every 20ms, currently if you have over 15 bots you start to notice the browser lagging (simply because of all the advanced collision detection going on). Is there any way to reduce the lag, can I make it any more efficient? P.s. sorrry for just posting a block of code, I can't see a way to make my point clear enough without! $.playground().registerCallback(function(){ //Movement Loop if(!pause) { for (var i in bots) { //bots - color, dir, x, y, z, spawned?, spawnerid, prevd var self = $('#b' + i); var current = bots[i]; if(bots[i][5]==1) { var xspeed = 0, yspeed = 0; if(current[1]==0) { yspeed = -D_SPEED; } else if(current[1]==1) { xspeed = D_SPEED; } else if(current[1]==2) { yspeed = D_SPEED; } else if(current[1]==3) { xspeed = -D_SPEED; } var x = current[2] + xspeed; var y = current[3] + yspeed; var z = current[3] + 120; if(current[2]>0&&x>PLAYGROUND_WIDTH||current[2]<0&&x<-GRID_SIZE|| current[3]>0&&y>PLAYGROUND_HEIGHT||current[3]<0&&y<-GRID_SIZE) { remove_bot(i, self); } else { if(current[7]!=current[1]) { self.setAnimation(colors[current[0]][current[1]]); bots[i][7] = current[1]; } if(self.css({"left": ""+(x)+"px", "top": ""+(y)+"px", "z-index": z})) { bots[i][2] = x; bots[i][3] = y; bots[i][4] = z; bots[i][8]++; } } } } $("#debug").html(dump(arrows)); $(".bot").each(function(){ var b_id = $(this).attr("id").substr(1); var collision = false; var c_bot = bots[b_id]; var b_x = c_bot[2]; var b_y = c_bot[3]; var b_d = c_bot[1]; $(this).collision(".arrow,#arrows").each(function(){ //Many thanks to Selim Arsever for this fix! var a_id = $(this).attr("id").substr(1); var piece = arrows[a_id]; var a_v = piece[0]; if(a_v==1) { var a_x = piece[2]; var a_y = piece[3]; var d_x = b_x-a_x; var d_y = b_y-a_y; if(d_x>=4&&d_x<=5&&d_y>=1&&d_y<=2) { //bots - color, dir, x, y, z, spawned?, spawnerid, prevd bots[b_id][7] = c_bot[1]; bots[b_id][1] = piece[1]; collision = true; } } }); if(!collision) { $(this).collision(".wall,#level").each(function(){ var w_id = $(this).attr("id").substr(1); var piece = pieces[w_id]; var w_x = piece[1]; var w_y = piece[2]; d_x = b_x-w_x; d_y = b_y-w_y; if(b_d==0&&d_x>=4&&d_x<=5&&d_y>=27&&d_y<=28) { kill_bot(b_id); collision = true; } //4 // 33 if(b_d==1&&d_x>=-12&&d_x<=-11&&d_y>=21&&d_y<=22) { kill_bot(b_id); collision = true; } //-14 // 21 if(b_d==2&&d_x>=4&&d_x<=5&&d_y>=-9&&d_y<=-8) { kill_bot(b_id); collision = true; } //4 // -9 if(b_d==3&&d_x>=22&&d_x<=23&&d_y>=20&&d_y<=21) { kill_bot(b_id); collision = true; } //22 // 21 }); } if(!collision&&c_bot[8]>GRID_MOVE) { $(this).collision(".spawn,#level").each(function(){ var s_id = $(this).attr("id").substr(1); var piece = pieces[s_id]; var s_x = piece[1]; var s_y = piece[2]; d_x = b_x-s_x; d_y = b_y-s_y; if(b_d==0&&d_x>=4&&d_x<=5&&d_y>=19&&d_y<=20) { kill_bot(b_id); collision = true; } //4 // 33 if(b_d==1&&d_x>=-14&&d_x<=-13&&d_y>=11&&d_y<=12) { kill_bot(b_id); collision = true; } //-14 // 21 if(b_d==2&&d_x>=4&&d_x<=5&&d_y>=-11&&d_y<=-10) { kill_bot(b_id); collision = true; } //4 // -9 if(b_d==3&&d_x>=22&&d_x<=23&&d_y>=11&&d_y<=12) { kill_bot(b_id); collision = true; } //22 // 21*/ }); } if(!collision) { $(this).collision(".exit,#level").each(function(){ var e_id = $(this).attr("id").substr(1); var piece = pieces[e_id]; var e_x = piece[1]; var e_y = piece[2]; d_x = b_x-e_x; d_y = b_y-e_y; if(d_x>=4&&d_x<=5&&d_y>=1&&d_y<=2) { current_bots++; bots[b_id] = false; $("#current_bots").html(current_bots); $("#b" + b_id).setAnimation(exit[2], function(node){$(node).fadeOut(200)}); } }); } if(!collision) { $(this).collision(".bot,#level").each(function(){ var bd_id = $(this).attr("id").substr(1); if(bd_id!=b_id) { var piece = bots[bd_id]; var bd_x = piece[2]; var bd_y = piece[3]; d_x = b_x-bd_x; d_y = b_y-bd_y; if(d_x>=0&&d_x<=2&&d_y>=0&&d_y<=2) { kill_bot(b_id); kill_bot(bd_id); collision = true; } } }); } }); } }, REFRESH_RATE); Many thanks,

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  • NetLogo 4.1 - implementation of a motorway ( Problem creating collision of cars )

    - by user206019
    Hi there, I am trying to create a simulation of motorway and the behaviour of the drivers in NetLogo. I have some questions that I m struggling to solve. Here is my code: globals [ selected-car ;; the currently selected car average-speed ;; average speed of all the cars look-ahead ] turtles-own [ speed ;; the current speed of the car speed-limit ;; the maximum speed of the car (different for all cars) lane ;; the current lane of the car target-lane ;; the desired lane of the car change? ;; true if the car wants to change lanes patience ;; the driver's current patience max-patience ;; the driver's maximum patience ] to setup ca import-drawing "my_road3.png" set-default-shape turtles "car" crt number_of_cars [ setup-cars ] end to setup-cars set color blue set size .9 set lane (random 3) set target-lane (lane + 1) setxy round random-xcor (lane + 1) set heading 90 set speed 0.1 + random 9.9 set speed-limit (((random 11) / 10) + 1) set change? false set max-patience ((random 50) + 10) set patience (max-patience - (random 10)) ;; make sure no two cars are on the same patch loop [ ifelse any? other turtles-here [ fd 1 ] [ stop ] ;if count turtles-here > 1 ; fd 0.1 ;if ; ;ifelse (any? turtles-on neighbors) or (count turtles-here > 1) ;[ ; ifelse (count turtles-here = 1) ; [ if any? turtles-on neighbors ; [ ; if distance min-one-of turtles-on neighbors [distance myself] > 0.9 ; [stop] ; ] ; ] ; [ fd 0.1 ] ;] ;[ stop ] ] end to go drive end to drive ;; first determine average speed of the cars set average-speed ((sum [speed] of turtles) / number_of_cars) ;set-current-plot "Car Speeds" ;set-current-plot-pen "average" ;plot average-speed ;set-current-plot-pen "max" ;plot (max [speed] of turtles) ;set-current-plot-pen "min" ;plot (abs (min [speed] of turtles) ) ;set-current-plot-pen "selected-car" ;plot ([speed] of selected-car) ask turtles [ ifelse (any? turtles-at 1 0) [ set speed ([speed] of (one-of (turtles-at 1 0))) decelerate ] [ ifelse (look-ahead = 2) [ ifelse (any? turtles-at 2 0) [ set speed ([speed] of (one-of turtles-at 2 0)) decelerate ] [ accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] [accelerate if count turtles-at 0 1 = 0 and ycor < 2.5 [lt 90 fd 1 rt 90] ] ] if (speed < 0.01) [ set speed 0.01 ] if (speed > speed-limit) [ set speed speed-limit ] ifelse (change? = false) [ signal ] [ change-lanes ] ;; Control for making sure no one crashes. ifelse (any? turtles-at 1 0) and (xcor != min-pxcor - .5) [ set speed [speed] of (one-of turtles-at 1 0) ] [ ifelse ((any? turtles-at 2 0) and (speed > 1.0)) [ set speed ([speed] of (one-of turtles-at 2 0)) fd 1 ] [jump speed] ] ] tick end ;; increase speed of cars to accelerate ;; turtle procedure set speed (speed + (speed-up / 1000)) end ;; reduce speed of cars to decelerate ;; turtle procedure set speed (speed - (slow-down / 1000)) end to signal ifelse (any? turtles-at 1 0) [ if ([speed] of (one-of (turtles-at 1 0))) < (speed) [ set change? true ] ] [ set change? false ] end ;; undergoes search algorithms to change-lanes ;; turtle procedure show ycor ifelse (patience <= 0) [ ifelse (max-patience <= 1) [ set max-patience (random 10) + 1 ] [ set max-patience (max-patience - (random 5)) ] set patience max-patience ifelse (target-lane = 0) [ set target-lane 1 set lane 0 ] [ set target-lane 0 set lane 1 ] ] [ set patience (patience - 1) ] ifelse (target-lane = lane) [ ifelse (target-lane = 0) [ set target-lane 1 set change? false ] [ set target-lane 0 set change? false ] ] [ ifelse (target-lane = 1) [ ifelse (pycor = 2) [ set lane 1 set change? false ] [ ifelse (not any? turtles-at 0 1) [ set ycor (ycor + 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] [ ifelse (pycor = -2) [ set lane 0 set change? false ] [ ifelse (not any? turtles-at 0 -1) [ set ycor (ycor - 1) ] [ ifelse (not any? turtles-at 1 0) [ set xcor (xcor + 1) ] [ decelerate if (speed <= 0) [ set speed 0.1 ] ] ] ] ] ] end I know its a bit messy because I am using code from other models from the library. I want to know how to create the collision of the cars. I can't think of any idea. As you notice my agent has almost the same size as the patch (I set it to 0.9 so that you can distinguish the space between 2 cars when they are set next to each other and I round the coordinates so that they are set to the centre of the patch). In my accelerate procedure I set my agent to turn left, move 1, turn right in a loop. I want to know if there's a command that lets me make the agent jump from one lane to the other (to the patch next to it on its left) without making it turn and move. And last, if you notice the code i created the car checks the patch that is next to it on the lane on its left and the patch in front of it and the back of it. So if the 3 patches on its left are empty then it can change lane. The fuzzy part is that when i run the setup and I press Go sometimes (not always) the car goes out of the 3 basic lanes. To understand this I have 7 lanes. The middle one which I don't use which is lane 0. Then there are 3 lanes on top of lane 0 and 3 below it. So the code I am using refers to the upper 3 lanes where I set the cars but for some reason some of the cars change lane and go to lane -3 then -2 and so forth. If someone can give me a tip I would really appreciate it. Thank you in advance. Tip: if you want to try this code in netlogo keep in mind that on interface tab I have 2 buttons one setup and one go as well as 3 sliders with names: number_of_cars , speed-up , slow-down.

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  • Out of memory exception during scrolling of listview

    - by user1761316
    I am using facebook data like postedpicture,profile picture,name,message in my listview.I am getting an OOM error while doing fast scrolling of listview. I am also having scrollviewlistener in my application that loads more data when the scrollbar reaches the bottom of the screen.I just want to know whether I need to change anything in this class. imageLoader.DisplayImage(postimage.get(position).replace(" ", "%20"), postimg) ; I am using the above line to call the method in this imageloader class to set the bitmap to imageview. Here is my imageloader class import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.Collections; import java.util.Map; import java.util.Stack; import java.util.WeakHashMap; import com.stellent.beerbro.Wall; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.RectF; import android.graphics.drawable.BitmapDrawable; import android.util.Log; import android.widget.ImageView; public class ImageLoader { MemoryCache memoryCache=new MemoryCache(); FileCache fileCache; private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>()); public ImageLoader(Context context){ //Make the background thead low priority. This way it will not affect the UI performance photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1); fileCache=new FileCache(context); } // final int stub_id=R.drawable.stub; public void DisplayImage(String url,ImageView imageView) { imageViews.put(imageView, url); System.gc(); // Bitmap bitmap=createScaledBitmap(memoryCache.get(url), 100,100,0); Bitmap bitmap=memoryCache.get(url); // Bitmap bitmaps=bitmap.createScaledBitmap(bitmap, 0, 100, 100); if(bitmap!=null) { imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); // imageView.setImageBitmap(getRoundedCornerBitmap( bitmap, 10,70,70)); // imageView.setImageBitmap(bitmap); // Log.v("first", "first"); } else { queuePhoto(url, imageView); // Log.v("second", "second"); } } private Bitmap createScaledBitmap(Bitmap bitmap, int i, int j, int k) { // TODO Auto-generated method stub return null; } private void queuePhoto(String url, ImageView imageView) { //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. photosQueue.Clean(imageView); PhotoToLoad p=new PhotoToLoad(url, imageView); synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.push(p); photosQueue.photosToLoad.notifyAll(); } //start thread if it's not started yet if(photoLoaderThread.getState()==Thread.State.NEW) photoLoaderThread.start(); } public Bitmap getBitmap(String url) { File f=fileCache.getFile(url); //from SD cache Bitmap b = decodeFile(f); if(b!=null) return b; //from web try { Bitmap bitmap=null; URL imageUrl = new URL(url); HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection(); conn.setConnectTimeout(30000); conn.setReadTimeout(30000); InputStream is=conn.getInputStream(); OutputStream os = new FileOutputStream(f); Utils.CopyStream(is, os); os.close(); bitmap = decodeFile(f); return bitmap; } catch (Exception ex){ ex.printStackTrace(); return null; } }//Lalit //decodes image and scales it to reduce memory consumption private Bitmap decodeFile(File f){ try { //decode image size BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeStream(new FileInputStream(f),null,o); //Find the correct scale value. It should be the power of 2. final int REQUIRED_SIZE=Wall.width; final int REQUIRED_SIZE1=Wall.height; // final int REQUIRED_SIZE=250; // int width_tmp=o.outWidth, height_tmp=o.outHeight; int scale=1; // while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE) //// scale*=2; while(true){ if(width_tmp/2<REQUIRED_SIZE && height_tmp/2<REQUIRED_SIZE1) break; width_tmp/=2; height_tmp/=2; scale*=2; } //decode with inSampleSize BitmapFactory.Options o2 = new BitmapFactory.Options(); o2.inSampleSize=scale; // o2.inSampleSize=2; return BitmapFactory.decodeStream(new FileInputStream(f), null, o2); } catch (FileNotFoundException e) {} return null; } //Task for the queue private class PhotoToLoad { public String url; public ImageView imageView; public PhotoToLoad(String u, ImageView i){ url=u; imageView=i; } } PhotosQueue photosQueue=new PhotosQueue(); public void stopThread() { photoLoaderThread.interrupt(); } //stores list of photos to download class PhotosQueue { private Stack<PhotoToLoad> photosToLoad=new Stack<PhotoToLoad>(); //removes all instances of this ImageView public void Clean(ImageView image) { for(int j=0 ;j<photosToLoad.size();){ if(photosToLoad.get(j).imageView==image) photosToLoad.remove(j); else ++j; } } } class PhotosLoader extends Thread { public void run() { try { while(true) { //thread waits until there are any images to load in the queue if(photosQueue.photosToLoad.size()==0) synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.wait(); } if(photosQueue.photosToLoad.size()!=0) { PhotoToLoad photoToLoad; synchronized(photosQueue.photosToLoad){ photoToLoad=photosQueue.photosToLoad.pop(); } Bitmap bmp=getBitmap(photoToLoad.url); memoryCache.put(photoToLoad.url, bmp); String tag=imageViews.get(photoToLoad.imageView); if(tag!=null && tag.equals(photoToLoad.url)){ BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView); Activity a=(Activity)photoToLoad.imageView.getContext(); a.runOnUiThread(bd); } } if(Thread.interrupted()) break; } } catch (InterruptedException e) { //allow thread to exit } } } PhotosLoader photoLoaderThread=new PhotosLoader(); //Used to display bitmap in the UI thread class BitmapDisplayer implements Runnable { Bitmap bitmap; ImageView imageView; public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;} public void run() { if(bitmap!=null) imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); } } public void clearCache() { memoryCache.clear(); fileCache.clear(); } public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels,int width,int height) { Bitmap output = Bitmap.createBitmap(width,height, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); final float roundPx = pixels; paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); paint.setColor(color); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } }

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  • How to declare a(n) vector/array of reducer objects in Cilk++?

    - by Jin
    Hi All, I had a problem when I am using Cilk++, an extension to C++ for parallel computing. I found that I can't declare a vector of reducer objects: typedef cilk::reducer_opadd<int> T_reducer; vector<T_reducer> bitmiss_vec; for (int i = 0; i < 24; ++i) { T_reducer r; bitmiss_vec.push_back(r); } However, when I compile the code with Cilk++, it complains at the push_back() line: cilk++ geneAttack.cilk -O1 -g -lcilkutil -o geneAttack /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In member function ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, const _Tp&) [with _Tp = cilk::reducer_opadd<int>]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:601: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/ext/new_allocator.h:107: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In member function ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:252: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:230: error: ‘cilk::reducer_opadd<Type>& cilk::reducer_opadd<Type>::operator=(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:256: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In static member function ‘static _BI2 std::__copy_backward<_BoolType, std::random_access_iterator_tag>::__copy_b(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*, bool _BoolType = false]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:465: instantiated from ‘_BI2 std::__copy_backward_aux(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:474: instantiated from ‘static _BI2 std::__copy_backward_normal<<anonymous>, <anonymous> >::__copy_b_n(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*, bool <anonymous> = false, bool <anonymous> = false]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:540: instantiated from ‘_BI2 std::copy_backward(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:253: instantiated from ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:230: error: ‘cilk::reducer_opadd<Type>& cilk::reducer_opadd<Type>::operator=(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:433: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In function ‘void std::_Construct(_T1*, const _T2&) [with _T1 = cilk::reducer_opadd<int>, _T2 = cilk::reducer_opadd<int>]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:87: instantiated from ‘_ForwardIterator std::__uninitialized_copy_aux(_InputIterator, _InputIterator, _ForwardIterator, std::__false_type) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:114: instantiated from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:254: instantiated from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*, _Tp = cilk::reducer_opadd<int>]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:275: instantiated from ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_construct.h:81: error: within this context make: *** [geneAttack] Error 1 jinchen@galactica:~/workspace/biometrics/genAttack$ make cilk++ geneAttack.cilk -O1 -g -lcilkutil -o geneAttack geneAttack.cilk: In function ‘int cilk cilk_main(int, char**)’: geneAttack.cilk:670: error: expected primary-expression before ‘,’ token geneAttack.cilk:670: error: expected primary-expression before ‘}’ token geneAttack.cilk:674: error: ‘bitmiss_vec’ was not declared in this scope make: *** [geneAttack] Error 1 The Cilk++ manule says it supports array/vector of reducers, although there are performance issues to consider: "If you create a large number of reducers (for example, an array or vector of reducers) you must be aware that there is an overhead at steal and reduce that is proportional to the number of reducers in the program. " Anyone knows what is going on? How should I declare/use vector of reducers? Thank you

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  • Increase efficiency of a loop with jQuery and GameQuery

    - by Pez Cuckow
    I have a game coded in jQuery where bots are moved around the screen. The below code is a loop that runs every 20ms, currently if you have over 15 bots you start to notice the browser lagging (simply because of all the advanced collision detection going on). Is there any way to reduce the lag, can I make it any more efficient? P.s. sorrry for just posting a block of code, I can't see a way to make my point clear enough without! $.playground().registerCallback(function(){ //Movement Loop if(!pause) { for (var i in bots) { //bots - color, dir, x, y, z, spawned?, spawnerid, prevd var self = $('#b' + i); var current = bots[i]; if(bots[i][5]==1) { var xspeed = 0, yspeed = 0; if(current[1]==0) { yspeed = -D_SPEED; } else if(current[1]==1) { xspeed = D_SPEED; } else if(current[1]==2) { yspeed = D_SPEED; } else if(current[1]==3) { xspeed = -D_SPEED; } var x = current[2] + xspeed; var y = current[3] + yspeed; var z = current[3] + 120; if(current[2]>0&&x>PLAYGROUND_WIDTH||current[2]<0&&x<-GRID_SIZE|| current[3]>0&&y>PLAYGROUND_HEIGHT||current[3]<0&&y<-GRID_SIZE) { remove_bot(i, self); } else { if(current[7]!=current[1]) { self.setAnimation(colors[current[0]][current[1]]); bots[i][7] = current[1]; } if(self.css({"left": ""+(x)+"px", "top": ""+(y)+"px", "z-index": z})) { bots[i][2] = x; bots[i][3] = y; bots[i][4] = z; bots[i][8]++; } } } } $("#debug").html(dump(arrows)); $(".bot").each(function(){ var b_id = $(this).attr("id").substr(1); var collision = false; var c_bot = bots[b_id]; var b_x = c_bot[2]; var b_y = c_bot[3]; var b_d = c_bot[1]; $(this).collision(".arrow,#arrows").each(function(){ //Many thanks to Selim Arsever for this fix! var a_id = $(this).attr("id").substr(1); var piece = arrows[a_id]; var a_v = piece[0]; if(a_v==1) { var a_x = piece[2]; var a_y = piece[3]; var d_x = b_x-a_x; var d_y = b_y-a_y; if(d_x>=4&&d_x<=5&&d_y>=1&&d_y<=2) { //bots - color, dir, x, y, z, spawned?, spawnerid, prevd bots[b_id][7] = c_bot[1]; bots[b_id][1] = piece[1]; collision = true; } } }); if(!collision) { $(this).collision(".wall,#level").each(function(){ var w_id = $(this).attr("id").substr(1); var piece = pieces[w_id]; var w_x = piece[1]; var w_y = piece[2]; d_x = b_x-w_x; d_y = b_y-w_y; if(b_d==0&&d_x>=4&&d_x<=5&&d_y>=27&&d_y<=28) { kill_bot(b_id); collision = true; } //4 // 33 if(b_d==1&&d_x>=-12&&d_x<=-11&&d_y>=21&&d_y<=22) { kill_bot(b_id); collision = true; } //-14 // 21 if(b_d==2&&d_x>=4&&d_x<=5&&d_y>=-9&&d_y<=-8) { kill_bot(b_id); collision = true; } //4 // -9 if(b_d==3&&d_x>=22&&d_x<=23&&d_y>=20&&d_y<=21) { kill_bot(b_id); collision = true; } //22 // 21 }); } if(!collision&&c_bot[8]>GRID_MOVE) { $(this).collision(".spawn,#level").each(function(){ var s_id = $(this).attr("id").substr(1); var piece = pieces[s_id]; var s_x = piece[1]; var s_y = piece[2]; d_x = b_x-s_x; d_y = b_y-s_y; if(b_d==0&&d_x>=4&&d_x<=5&&d_y>=19&&d_y<=20) { kill_bot(b_id); collision = true; } //4 // 33 if(b_d==1&&d_x>=-14&&d_x<=-13&&d_y>=11&&d_y<=12) { kill_bot(b_id); collision = true; } //-14 // 21 if(b_d==2&&d_x>=4&&d_x<=5&&d_y>=-11&&d_y<=-10) { kill_bot(b_id); collision = true; } //4 // -9 if(b_d==3&&d_x>=22&&d_x<=23&&d_y>=11&&d_y<=12) { kill_bot(b_id); collision = true; } //22 // 21*/ }); } if(!collision) { $(this).collision(".exit,#level").each(function(){ var e_id = $(this).attr("id").substr(1); var piece = pieces[e_id]; var e_x = piece[1]; var e_y = piece[2]; d_x = b_x-e_x; d_y = b_y-e_y; if(d_x>=4&&d_x<=5&&d_y>=1&&d_y<=2) { current_bots++; bots[b_id] = false; $("#current_bots").html(current_bots); $("#b" + b_id).setAnimation(exit[2], function(node){$(node).fadeOut(200)}); } }); } if(!collision) { $(this).collision(".bot,#level").each(function(){ var bd_id = $(this).attr("id").substr(1); if(bd_id!=b_id) { var piece = bots[bd_id]; var bd_x = piece[2]; var bd_y = piece[3]; d_x = b_x-bd_x; d_y = b_y-bd_y; if(d_x>=0&&d_x<=2&&d_y>=0&&d_y<=2) { kill_bot(b_id); kill_bot(bd_id); collision = true; } } }); } }); } }, REFRESH_RATE); Many thanks,

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  • How to declare a vector or array of reducer objects in Cilk++?

    - by Jin
    Hi All, I had a problem when I am using Cilk++, an extension to C++ for parallel computing. I found that I can't declare a vector of reducer objects: typedef cilk::reducer_opadd<int> T_reducer; vector<T_reducer> bitmiss_vec; for (int i = 0; i < 24; ++i) { T_reducer r; bitmiss_vec.push_back(r); } However, when I compile the code with Cilk++, it complains at the push_back() line: cilk++ geneAttack.cilk -O1 -g -lcilkutil -o geneAttack /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In member function ‘void __gnu_cxx::new_allocator<_Tp>::construct(_Tp*, const _Tp&) [with _Tp = cilk::reducer_opadd<int>]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:601: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/ext/new_allocator.h:107: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In member function ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:252: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:230: error: ‘cilk::reducer_opadd<Type>& cilk::reducer_opadd<Type>::operator=(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:256: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In static member function ‘static _BI2 std::__copy_backward<_BoolType, std::random_access_iterator_tag>::__copy_b(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*, bool _BoolType = false]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:465: instantiated from ‘_BI2 std::__copy_backward_aux(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:474: instantiated from ‘static _BI2 std::__copy_backward_normal<<anonymous>, <anonymous> >::__copy_b_n(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*, bool <anonymous> = false, bool <anonymous> = false]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:540: instantiated from ‘_BI2 std::copy_backward(_BI1, _BI1, _BI2) [with _BI1 = cilk::reducer_opadd<int>*, _BI2 = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:253: instantiated from ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:230: error: ‘cilk::reducer_opadd<Type>& cilk::reducer_opadd<Type>::operator=(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_algobase.h:433: error: within this context /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h: In function ‘void std::_Construct(_T1*, const _T2&) [with _T1 = cilk::reducer_opadd<int>, _T2 = cilk::reducer_opadd<int>]’: /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:87: instantiated from ‘_ForwardIterator std::__uninitialized_copy_aux(_InputIterator, _InputIterator, _ForwardIterator, std::__false_type) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:114: instantiated from ‘_ForwardIterator std::uninitialized_copy(_InputIterator, _InputIterator, _ForwardIterator) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_uninitialized.h:254: instantiated from ‘_ForwardIterator std::__uninitialized_copy_a(_InputIterator, _InputIterator, _ForwardIterator, std::allocator<_Tp>) [with _InputIterator = cilk::reducer_opadd<int>*, _ForwardIterator = cilk::reducer_opadd<int>*, _Tp = cilk::reducer_opadd<int>]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/vector.tcc:275: instantiated from ‘void std::vector<_Tp, _Alloc>::_M_insert_aux(__gnu_cxx::__normal_iterator<typename std::_Vector_base<_Tp, _Alloc>::_Tp_alloc_type::pointer, std::vector<_Tp, _Alloc> >, const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_vector.h:605: instantiated from ‘void std::vector<_Tp, _Alloc>::push_back(const _Tp&) [with _Tp = cilk::reducer_opadd<int>, _Alloc = std::allocator<cilk::reducer_opadd<int> >]’ geneAttack.cilk:667: instantiated from here /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/cilk++/reducer_opadd.h:229: error: ‘cilk::reducer_opadd<Type>::reducer_opadd(const cilk::reducer_opadd<Type>&) [with Type = int]’ is private /usr/local/cilk/bin/../lib/gcc/x86_64-unknown-linux-gnu/4.2.4/../../../../include/c++/4.2.4/bits/stl_construct.h:81: error: within this context make: *** [geneAttack] Error 1 jinchen@galactica:~/workspace/biometrics/genAttack$ make cilk++ geneAttack.cilk -O1 -g -lcilkutil -o geneAttack geneAttack.cilk: In function ‘int cilk cilk_main(int, char**)’: geneAttack.cilk:670: error: expected primary-expression before ‘,’ token geneAttack.cilk:670: error: expected primary-expression before ‘}’ token geneAttack.cilk:674: error: ‘bitmiss_vec’ was not declared in this scope make: *** [geneAttack] Error 1 The Cilk++ manule says it supports array/vector of reducers, although there are performance issues to consider: "If you create a large number of reducers (for example, an array or vector of reducers) you must be aware that there is an overhead at steal and reduce that is proportional to the number of reducers in the program. " Anyone knows what is going on? How should I declare/use vector of reducers? Thank you

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  • OpenVPN Client timing out

    - by Austin
    I recently installed OpenVPN on my Ubuntu VPS. Whenenver I try to connect to it, I can establish a connection just fine. However, everything I try to connect to times out. If I try to ping something, it will resolve the IP, but will time out after resolving the IP. (So DNS Server seems to be working correctly) My server.conf has this relevant information (At least I think it's relevant. I'm not sure if you need more or not) # Which local IP address should OpenVPN # listen on? (optional) ;local a.b.c.d # Which TCP/UDP port should OpenVPN listen on? # If you want to run multiple OpenVPN instances # on the same machine, use a different port # number for each one. You will need to # open up this port on your firewall. port 1194 # TCP or UDP server? ;proto tcp proto udp # "dev tun" will create a routed IP tunnel, # "dev tap" will create an ethernet tunnel. # Use "dev tap0" if you are ethernet bridging # and have precreated a tap0 virtual interface # and bridged it with your ethernet interface. # If you want to control access policies # over the VPN, you must create firewall # rules for the the TUN/TAP interface. # On non-Windows systems, you can give # an explicit unit number, such as tun0. # On Windows, use "dev-node" for this. # On most systems, the VPN will not function # unless you partially or fully disable # the firewall for the TUN/TAP interface. ;dev tap dev tun # Windows needs the TAP-Win32 adapter name # from the Network Connections panel if you # have more than one. On XP SP2 or higher, # you may need to selectively disable the # Windows firewall for the TAP adapter. # Non-Windows systems usually don't need this. ;dev-node MyTap # SSL/TLS root certificate (ca), certificate # (cert), and private key (key). Each client # and the server must have their own cert and # key file. The server and all clients will # use the same ca file. # # See the "easy-rsa" directory for a series # of scripts for generating RSA certificates # and private keys. Remember to use # a unique Common Name for the server # and each of the client certificates. # # Any X509 key management system can be used. # OpenVPN can also use a PKCS #12 formatted key file # (see "pkcs12" directive in man page). ca ca.crt cert server.crt key server.key # This file should be kept secret # Diffie hellman parameters. # Generate your own with: # openssl dhparam -out dh1024.pem 1024 # Substitute 2048 for 1024 if you are using # 2048 bit keys. dh dh1024.pem # Configure server mode and supply a VPN subnet # for OpenVPN to draw client addresses from. # The server will take 10.8.0.1 for itself, # the rest will be made available to clients. # Each client will be able to reach the server # on 10.8.0.1. Comment this line out if you are # ethernet bridging. See the man page for more info. server 10.8.0.0 255.255.255.0 # Maintain a record of client <-> virtual IP address # associations in this file. If OpenVPN goes down or # is restarted, reconnecting clients can be assigned # the same virtual IP address from the pool that was # previously assigned. ifconfig-pool-persist ipp.txt # Configure server mode for ethernet bridging. # You must first use your OS's bridging capability # to bridge the TAP interface with the ethernet # NIC interface. Then you must manually set the # IP/netmask on the bridge interface, here we # assume 10.8.0.4/255.255.255.0. Finally we # must set aside an IP range in this subnet # (start=10.8.0.50 end=10.8.0.100) to allocate # to connecting clients. Leave this line commented # out unless you are ethernet bridging. ;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100 # Configure server mode for ethernet bridging # using a DHCP-proxy, where clients talk # to the OpenVPN server-side DHCP server # to receive their IP address allocation # and DNS server addresses. You must first use # your OS's bridging capability to bridge the TAP # interface with the ethernet NIC interface. # Note: this mode only works on clients (such as # Windows), where the client-side TAP adapter is # bound to a DHCP client. ;server-bridge # Push routes to the client to allow it # to reach other private subnets behind # the server. Remember that these # private subnets will also need # to know to route the OpenVPN client # address pool (10.8.0.0/255.255.255.0) # back to the OpenVPN server. ;push "route 192.168.10.0 255.255.255.0" ;push "route 192.168.20.0 255.255.255.0" # To assign specific IP addresses to specific # clients or if a connecting client has a private # subnet behind it that should also have VPN access, # use the subdirectory "ccd" for client-specific # configuration files (see man page for more info). # EXAMPLE: Suppose the client # having the certificate common name "Thelonious" # also has a small subnet behind his connecting # machine, such as 192.168.40.128/255.255.255.248. # First, uncomment out these lines: ;client-config-dir ccd ;route 192.168.40.128 255.255.255.248 # Then create a file ccd/Thelonious with this line: # iroute 192.168.40.128 255.255.255.248 # This will allow Thelonious' private subnet to # access the VPN. This example will only work # if you are routing, not bridging, i.e. you are # using "dev tun" and "server" directives. # EXAMPLE: Suppose you want to give # Thelonious a fixed VPN IP address of 10.9.0.1. # First uncomment out these lines: ;client-config-dir ccd ;route 10.9.0.0 255.255.255.252 # Then add this line to ccd/Thelonious: # ifconfig-push 10.9.0.1 10.9.0.2 # Suppose that you want to enable different # firewall access policies for different groups # of clients. There are two methods: # (1) Run multiple OpenVPN daemons, one for each # group, and firewall the TUN/TAP interface # for each group/daemon appropriately. # (2) (Advanced) Create a script to dynamically # modify the firewall in response to access # from different clients. See man # page for more info on learn-address script. ;learn-address ./script # If enabled, this directive will configure # all clients to redirect their default # network gateway through the VPN, causing # all IP traffic such as web browsing and # and DNS lookups to go through the VPN # (The OpenVPN server machine may need to NAT # or bridge the TUN/TAP interface to the internet # in order for this to work properly). push "redirect-gateway def1 bypass-dhcp" push "dhcp-option DNS 8.8.8.8" # Certain Windows-specific network settings # can be pushed to clients, such as DNS # or WINS server addresses. CAVEAT: # http://openvpn.net/faq.html#dhcpcaveats # The addresses below refer to the public # DNS servers provided by opendns.com. ;push "dhcp-option DNS 8.8.8.8" push "dhcp-option DNS 8.8.4.4" # Uncomment this directive to allow different # clients to be able to "see" each other. # By default, clients will only see the server. # To force clients to only see the server, you # will also need to appropriately firewall the # server's TUN/TAP interface. ;client-to-client # Uncomment this directive if multiple clients # might connect with the same certificate/key # files or common names. This is recommended # only for testing purposes. For production use, # each client should have its own certificate/key # pair. # # IF YOU HAVE NOT GENERATED INDIVIDUAL # CERTIFICATE/KEY PAIRS FOR EACH CLIENT, # EACH HAVING ITS OWN UNIQUE "COMMON NAME", # UNCOMMENT THIS LINE OUT. ;duplicate-cn # The keepalive directive causes ping-like # messages to be sent back and forth over # the link so that each side knows when # the other side has gone down. # Ping every 10 seconds, assume that remote # peer is down if no ping received during # a 120 second time period. keepalive 10 120 # For extra security beyond that provided # by SSL/TLS, create an "HMAC firewall" # to help block DoS attacks and UDP port flooding. # # Generate with: # openvpn --genkey --secret ta.key # # The server and each client must have # a copy of this key. # The second parameter should be '0' # on the server and '1' on the clients. ;tls-auth ta.key 0 # This file is secret # Select a cryptographic cipher. # This config item must be copied to # the client config file as well. ;cipher BF-CBC # Blowfish (default) ;cipher AES-128-CBC # AES ;cipher DES-EDE3-CBC # Triple-DES # Enable compression on the VPN link. # If you enable it here, you must also # enable it in the client config file. comp-lzo # The maximum number of concurrently connected # clients we want to allow. ;max-clients 100 # It's a good idea to reduce the OpenVPN # daemon's privileges after initialization. # # You can uncomment this out on # non-Windows systems. ;user nobody ;group nogroup # The persist options will try to avoid # accessing certain resources on restart # that may no longer be accessible because # of the privilege downgrade. persist-key persist-tun # Output a short status file showing # current connections, truncated # and rewritten every minute. status openvpn-status.log # By default, log messages will go to the syslog (or # on Windows, if running as a service, they will go to # the "\Program Files\OpenVPN\log" directory). # Use log or log-append to override this default. # "log" will truncate the log file on OpenVPN startup, # while "log-append" will append to it. Use one # or the other (but not both). ;log openvpn.log ;log-append openvpn.log # Set the appropriate level of log # file verbosity. # # 0 is silent, except for fatal errors # 4 is reasonable for general usage # 5 and 6 can help to debug connection problems # 9 is extremely verbose verb 3 # Silence repeating messages. At most 20 # sequential messages of the same message # category will be output to the log. ;mute 20 I've tried on multiple computers by the way. The same result on all of them. What could be wrong? Thanks in advance, and if you need other information I'll gladly post it. Information for new comments root@vps:~# iptables -L -n -v Chain INPUT (policy ACCEPT 862K packets, 51M bytes) pkts bytes target prot opt in out source destination Chain FORWARD (policy ACCEPT 3 packets, 382 bytes) pkts bytes target prot opt in out source destination 0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED 4641 298K ACCEPT all -- * * 10.8.0.0/24 0.0.0.0/0 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable Chain OUTPUT (policy ACCEPT 1671K packets, 2378M bytes) pkts bytes target prot opt in out source destination And root@vps:~# iptables -t nat -L -n -v Chain PREROUTING (policy ACCEPT 17937 packets, 2013K bytes) pkts bytes target prot opt in out source destination Chain POSTROUTING (policy ACCEPT 8975 packets, 562K bytes) pkts bytes target prot opt in out source destination 1579 103K SNAT all -- * * 10.8.0.0/24 0.0.0.0/0 to:SERVERIP Chain OUTPUT (policy ACCEPT 8972 packets, 562K bytes) pkts bytes target prot opt in out source destination

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  • FreeBSD 8.1 unstable network connection

    - by frankcheong
    I have three FreeBSD 8.1 running on three different hardware and therefore consist of different network adapter as well (bce, bge and igb). I found that the network connection is kind of unstable which I have tried to scp some 10MB file and found that I cannot always get the files completed successfully. I have further checked with my network admin and he claim that the problem is being caused by the network driver which cannot support the load whereby he tried to ping using huge packet size (around 15k) and my server will drop packet consistently at a regular interval. I found that this statement may not be valid since the three server is using three different network drive and it would be quite impossible that the same problem is being caused by three different network adapter and thus different network driver. Since then I have tried to tune up the performance by playing around with the /etc/sysctl.conf figures with no luck. kern.ipc.somaxconn=1024 kern.ipc.shmall=3276800 kern.ipc.shmmax=1638400000 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # Required by pf net.inet.ip.forwarding=1 #Network Performance Tuning kern.ipc.maxsockbuf=16777216 net.inet.tcp.rfc1323=1 net.inet.tcp.sendbuf_max=16777216 net.inet.tcp.recvbuf_max=16777216 # Setting specifically for 1 or even 10Gbps network net.local.stream.sendspace=262144 net.local.stream.recvspace=262144 net.inet.tcp.local_slowstart_flightsize=10 net.inet.tcp.nolocaltimewait=1 net.inet.tcp.mssdflt=1460 net.inet.tcp.sendbuf_auto=1 net.inet.tcp.sendbuf_inc=16384 net.inet.tcp.recvbuf_auto=1 net.inet.tcp.recvbuf_inc=524288 net.inet.tcp.sendspace=262144 net.inet.tcp.recvspace=262144 net.inet.udp.recvspace=262144 kern.ipc.maxsockbuf=16777216 kern.ipc.nmbclusters=32768 net.inet.tcp.delayed_ack=1 net.inet.tcp.delacktime=100 net.inet.tcp.slowstart_flightsize=179 net.inet.tcp.inflight.enable=1 net.inet.tcp.inflight.min=6144 # Reduce the cache size of slow start connection net.inet.tcp.hostcache.expire=1 Our network admin also claim that they see quite a lot of network up and down from their cisco switch log while I cannot find any up down message inside the dmesg. Have further checked the netstat -s but dont have concrete idea. tcp: 133695291 packets sent 39408539 data packets (3358837321 bytes) 61868 data packets (89472844 bytes) retransmitted 24 data packets unnecessarily retransmitted 0 resends initiated by MTU discovery 50756141 ack-only packets (2148 delayed) 0 URG only packets 0 window probe packets 4372385 window update packets 39781869 control packets 134898031 packets received 72339403 acks (for 3357601899 bytes) 190712 duplicate acks 0 acks for unsent data 59339201 packets (3647021974 bytes) received in-sequence 114 completely duplicate packets (135202 bytes) 27 old duplicate packets 0 packets with some dup. data (0 bytes duped) 42090 out-of-order packets (60817889 bytes) 0 packets (0 bytes) of data after window 0 window probes 3953896 window update packets 64181 packets received after close 0 discarded for bad checksums 0 discarded for bad header offset fields 0 discarded because packet too short 45192 discarded due to memory problems 19945391 connection requests 1323420 connection accepts 0 bad connection attempts 0 listen queue overflows 0 ignored RSTs in the windows 21133581 connections established (including accepts) 21268724 connections closed (including 32737 drops) 207874 connections updated cached RTT on close 207874 connections updated cached RTT variance on close 132439 connections updated cached ssthresh on close 42392 embryonic connections dropped 72339338 segments updated rtt (of 69477829 attempts) 390871 retransmit timeouts 0 connections dropped by rexmit timeout 0 persist timeouts 0 connections dropped by persist timeout 0 Connections (fin_wait_2) dropped because of timeout 13990 keepalive timeouts 2 keepalive probes sent 13988 connections dropped by keepalive 173044 correct ACK header predictions 36947371 correct data packet header predictions 1323420 syncache entries added 0 retransmitted 0 dupsyn 0 dropped 1323420 completed 0 bucket overflow 0 cache overflow 0 reset 0 stale 0 aborted 0 badack 0 unreach 0 zone failures 1323420 cookies sent 0 cookies received 1864 SACK recovery episodes 18005 segment rexmits in SACK recovery episodes 26066896 byte rexmits in SACK recovery episodes 147327 SACK options (SACK blocks) received 87473 SACK options (SACK blocks) sent 0 SACK scoreboard overflow 0 packets with ECN CE bit set 0 packets with ECN ECT(0) bit set 0 packets with ECN ECT(1) bit set 0 successful ECN handshakes 0 times ECN reduced the congestion window udp: 5141258 datagrams received 0 with incomplete header 0 with bad data length field 0 with bad checksum 1 with no checksum 0 dropped due to no socket 129616 broadcast/multicast datagrams undelivered 0 dropped due to full socket buffers 0 not for hashed pcb 5011642 delivered 5016050 datagrams output 0 times multicast source filter matched sctp: 0 input packets 0 datagrams 0 packets that had data 0 input SACK chunks 0 input DATA chunks 0 duplicate DATA chunks 0 input HB chunks 0 HB-ACK chunks 0 input ECNE chunks 0 input AUTH chunks 0 chunks missing AUTH 0 invalid HMAC ids received 0 invalid secret ids received 0 auth failed 0 fast path receives all one chunk 0 fast path multi-part data 0 output packets 0 output SACKs 0 output DATA chunks 0 retransmitted DATA chunks 0 fast retransmitted DATA chunks 0 FR's that happened more than once to same chunk 0 intput HB chunks 0 output ECNE chunks 0 output AUTH chunks 0 ip_output error counter Packet drop statistics: 0 from middle box 0 from end host 0 with data 0 non-data, non-endhost 0 non-endhost, bandwidth rep only 0 not enough for chunk header 0 not enough data to confirm 0 where process_chunk_drop said break 0 failed to find TSN 0 attempt reverse TSN lookup 0 e-host confirms zero-rwnd 0 midbox confirms no space 0 data did not match TSN 0 TSN's marked for Fast Retran Timeouts: 0 iterator timers fired 0 T3 data time outs 0 window probe (T3) timers fired 0 INIT timers fired 0 sack timers fired 0 shutdown timers fired 0 heartbeat timers fired 0 a cookie timeout fired 0 an endpoint changed its cookiesecret 0 PMTU timers fired 0 shutdown ack timers fired 0 shutdown guard timers fired 0 stream reset timers fired 0 early FR timers fired 0 an asconf timer fired 0 auto close timer fired 0 asoc free timers expired 0 inp free timers expired 0 packet shorter than header 0 checksum error 0 no endpoint for port 0 bad v-tag 0 bad SID 0 no memory 0 number of multiple FR in a RTT window 0 RFC813 allowed sending 0 RFC813 does not allow sending 0 times max burst prohibited sending 0 look ahead tells us no memory in interface 0 numbers of window probes sent 0 times an output error to clamp down on next user send 0 times sctp_senderrors were caused from a user 0 number of in data drops due to chunk limit reached 0 number of in data drops due to rwnd limit reached 0 times a ECN reduced the cwnd 0 used express lookup via vtag 0 collision in express lookup 0 times the sender ran dry of user data on primary 0 same for above 0 sacks the slow way 0 window update only sacks sent 0 sends with sinfo_flags !=0 0 unordered sends 0 sends with EOF flag set 0 sends with ABORT flag set 0 times protocol drain called 0 times we did a protocol drain 0 times recv was called with peek 0 cached chunks used 0 cached stream oq's used 0 unread messages abandonded by close 0 send burst avoidance, already max burst inflight to net 0 send cwnd full avoidance, already max burst inflight to net 0 number of map array over-runs via fwd-tsn's ip: 137814085 total packets received 0 bad header checksums 0 with size smaller than minimum 0 with data size < data length 0 with ip length > max ip packet size 0 with header length < data size 0 with data length < header length 0 with bad options 0 with incorrect version number 1200 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 300 packets reassembled ok 137813009 packets for this host 530 packets for unknown/unsupported protocol 0 packets forwarded (0 packets fast forwarded) 61 packets not forwardable 0 packets received for unknown multicast group 0 redirects sent 137234598 packets sent from this host 0 packets sent with fabricated ip header 685307 output packets dropped due to no bufs, etc. 52 output packets discarded due to no route 300 output datagrams fragmented 1200 fragments created 0 datagrams that can't be fragmented 0 tunneling packets that can't find gif 0 datagrams with bad address in header icmp: 0 calls to icmp_error 0 errors not generated in response to an icmp message Output histogram: echo reply: 305 0 messages with bad code fields 0 messages less than the minimum length 0 messages with bad checksum 0 messages with bad length 0 multicast echo requests ignored 0 multicast timestamp requests ignored Input histogram: destination unreachable: 530 echo: 305 305 message responses generated 0 invalid return addresses 0 no return routes ICMP address mask responses are disabled igmp: 0 messages received 0 messages received with too few bytes 0 messages received with wrong TTL 0 messages received with bad checksum 0 V1/V2 membership queries received 0 V3 membership queries received 0 membership queries received with invalid field(s) 0 general queries received 0 group queries received 0 group-source queries received 0 group-source queries dropped 0 membership reports received 0 membership reports received with invalid field(s) 0 membership reports received for groups to which we belong 0 V3 reports received without Router Alert 0 membership reports sent arp: 376748 ARP requests sent 3207 ARP replies sent 245245 ARP requests received 80845 ARP replies received 326090 ARP packets received 267712 total packets dropped due to no ARP entry 108876 ARP entrys timed out 0 Duplicate IPs seen ip6: 2226633 total packets received 0 with size smaller than minimum 0 with data size < data length 0 with bad options 0 with incorrect version number 0 fragments received 0 fragments dropped (dup or out of space) 0 fragments dropped after timeout 0 fragments that exceeded limit 0 packets reassembled ok 2226633 packets for this host 0 packets forwarded 0 packets not forwardable 0 redirects sent 2226633 packets sent from this host 0 packets sent with fabricated ip header 0 output packets dropped due to no bufs, etc. 8 output packets discarded due to no route 0 output datagrams fragmented 0 fragments created 0 datagrams that can't be fragmented 0 packets that violated scope rules 0 multicast packets which we don't join Input histogram: UDP: 2226633 Mbuf statistics: 962679 one mbuf 1263954 one ext mbuf 0 two or more ext mbuf 0 packets whose headers are not continuous 0 tunneling packets that can't find gif 0 packets discarded because of too many headers 0 failures of source address selection Source addresses selection rule applied: icmp6: 0 calls to icmp6_error 0 errors not generated in response to an icmp6 message 0 errors not generated because of rate limitation 0 messages with bad code fields 0 messages < minimum length 0 bad checksums 0 messages with bad length Histogram of error messages to be generated: 0 no route 0 administratively prohibited 0 beyond scope 0 address unreachable 0 port unreachable 0 packet too big 0 time exceed transit 0 time exceed reassembly 0 erroneous header field 0 unrecognized next header 0 unrecognized option 0 redirect 0 unknown 0 message responses generated 0 messages with too many ND options 0 messages with bad ND options 0 bad neighbor solicitation messages 0 bad neighbor advertisement messages 0 bad router solicitation messages 0 bad router advertisement messages 0 bad redirect messages 0 path MTU changes rip6: 0 messages received 0 checksum calculations on inbound 0 messages with bad checksum 0 messages dropped due to no socket 0 multicast messages dropped due to no socket 0 messages dropped due to full socket buffers 0 delivered 0 datagrams output netstat -m 516/5124/5640 mbufs in use (current/cache/total) 512/1634/2146/32768 mbuf clusters in use (current/cache/total/max) 512/1536 mbuf+clusters out of packet secondary zone in use (current/cache) 0/1303/1303/12800 4k (page size) jumbo clusters in use (current/cache/total/max) 0/0/0/6400 9k jumbo clusters in use (current/cache/total/max) 0/0/0/3200 16k jumbo clusters in use (current/cache/total/max) 1153K/9761K/10914K bytes allocated to network (current/cache/total) 0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters) 0/0/0 requests for jumbo clusters denied (4k/9k/16k) 0/8/6656 sfbufs in use (current/peak/max) 0 requests for sfbufs denied 0 requests for sfbufs delayed 0 requests for I/O initiated by sendfile 0 calls to protocol drain routines Anyone got an idea what might be the possible cause?

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  • What's New in ASP.NET 4

    - by Navaneeth
    The .NET Framework version 4 includes enhancements for ASP.NET 4 in targeted areas. Visual Studio 2010 and Microsoft Visual Web Developer Express also include enhancements and new features for improved Web development. This document provides an overview of many of the new features that are included in the upcoming release. This topic contains the following sections: ASP.NET Core Services ASP.NET Web Forms ASP.NET MVC Dynamic Data ASP.NET Chart Control Visual Web Developer Enhancements Web Application Deployment with Visual Studio 2010 Enhancements to ASP.NET Multi-Targeting ASP.NET Core Services ASP.NET 4 introduces many features that improve core ASP.NET services such as output caching and session state storage. Extensible Output Caching Since the time that ASP.NET 1.0 was released, output caching has enabled developers to store the generated output of pages, controls, and HTTP responses in memory. On subsequent Web requests, ASP.NET can serve content more quickly by retrieving the generated output from memory instead of regenerating the output from scratch. However, this approach has a limitation — generated content always has to be stored in memory. On servers that experience heavy traffic, the memory requirements for output caching can compete with memory requirements for other parts of a Web application. ASP.NET 4 adds extensibility to output caching that enables you to configure one or more custom output-cache providers. Output-cache providers can use any storage mechanism to persist HTML content. These storage options can include local or remote disks, cloud storage, and distributed cache engines. Output-cache provider extensibility in ASP.NET 4 lets you design more aggressive and more intelligent output-caching strategies for Web sites. For example, you can create an output-cache provider that caches the "Top 10" pages of a site in memory, while caching pages that get lower traffic on disk. Alternatively, you can cache every vary-by combination for a rendered page, but use a distributed cache so that the memory consumption is offloaded from front-end Web servers. You create a custom output-cache provider as a class that derives from the OutputCacheProvider type. You can then configure the provider in the Web.config file by using the new providers subsection of the outputCache element For more information and for examples that show how to configure the output cache, see outputCache Element for caching (ASP.NET Settings Schema). For more information about the classes that support caching, see the documentation for the OutputCache and OutputCacheProvider classes. By default, in ASP.NET 4, all HTTP responses, rendered pages, and controls use the in-memory output cache. The defaultProvider attribute for ASP.NET is AspNetInternalProvider. You can change the default output-cache provider used for a Web application by specifying a different provider name for defaultProvider attribute. In addition, you can select different output-cache providers for individual control and for individual requests and programmatically specify which provider to use. For more information, see the HttpApplication.GetOutputCacheProviderName(HttpContext) method. The easiest way to choose a different output-cache provider for different Web user controls is to do so declaratively by using the new providerName attribute in a page or control directive, as shown in the following example: <%@ OutputCache Duration="60" VaryByParam="None" providerName="DiskCache" %> Preloading Web Applications Some Web applications must load large amounts of data or must perform expensive initialization processing before serving the first request. In earlier versions of ASP.NET, for these situations you had to devise custom approaches to "wake up" an ASP.NET application and then run initialization code during the Application_Load method in the Global.asax file. To address this scenario, a new application preload manager (autostart feature) is available when ASP.NET 4 runs on IIS 7.5 on Windows Server 2008 R2. The preload feature provides a controlled approach for starting up an application pool, initializing an ASP.NET application, and then accepting HTTP requests. It lets you perform expensive application initialization prior to processing the first HTTP request. For example, you can use the application preload manager to initialize an application and then signal a load-balancer that the application was initialized and ready to accept HTTP traffic. To use the application preload manager, an IIS administrator sets an application pool in IIS 7.5 to be automatically started by using the following configuration in the applicationHost.config file: <applicationPools> <add name="MyApplicationPool" startMode="AlwaysRunning" /> </applicationPools> Because a single application pool can contain multiple applications, you specify individual applications to be automatically started by using the following configuration in the applicationHost.config file: <sites> <site name="MySite" id="1"> <application path="/" serviceAutoStartEnabled="true" serviceAutoStartProvider="PrewarmMyCache" > <!-- Additional content --> </application> </site> </sites> <!-- Additional content --> <serviceAutoStartProviders> <add name="PrewarmMyCache" type="MyNamespace.CustomInitialization, MyLibrary" /> </serviceAutoStartProviders> When an IIS 7.5 server is cold-started or when an individual application pool is recycled, IIS 7.5 uses the information in the applicationHost.config file to determine which Web applications have to be automatically started. For each application that is marked for preload, IIS7.5 sends a request to ASP.NET 4 to start the application in a state during which the application temporarily does not accept HTTP requests. When it is in this state, ASP.NET instantiates the type defined by the serviceAutoStartProvider attribute (as shown in the previous example) and calls into its public entry point. You create a managed preload type that has the required entry point by implementing the IProcessHostPreloadClient interface, as shown in the following example: public class CustomInitialization : System.Web.Hosting.IProcessHostPreloadClient { public void Preload(string[] parameters) { // Perform initialization. } } After your initialization code runs in the Preload method and after the method returns, the ASP.NET application is ready to process requests. Permanently Redirecting a Page Content in Web applications is often moved over the lifetime of the application. This can lead to links to be out of date, such as the links that are returned by search engines. In ASP.NET, developers have traditionally handled requests to old URLs by using the Redirect method to forward a request to the new URL. However, the Redirect method issues an HTTP 302 (Found) response (which is used for a temporary redirect). This results in an extra HTTP round trip. ASP.NET 4 adds a RedirectPermanent helper method that makes it easy to issue HTTP 301 (Moved Permanently) responses, as in the following example: RedirectPermanent("/newpath/foroldcontent.aspx"); Search engines and other user agents that recognize permanent redirects will store the new URL that is associated with the content, which eliminates the unnecessary round trip made by the browser for temporary redirects. Session State Compression By default, ASP.NET provides two options for storing session state across a Web farm. The first option is a session state provider that invokes an out-of-process session state server. The second option is a session state provider that stores data in a Microsoft SQL Server database. Because both options store state information outside a Web application's worker process, session state has to be serialized before it is sent to remote storage. If a large amount of data is saved in session state, the size of the serialized data can become very large. ASP.NET 4 introduces a new compression option for both kinds of out-of-process session state providers. By using this option, applications that have spare CPU cycles on Web servers can achieve substantial reductions in the size of serialized session state data. You can set this option using the new compressionEnabled attribute of the sessionState element in the configuration file. When the compressionEnabled configuration option is set to true, ASP.NET compresses (and decompresses) serialized session state by using the .NET Framework GZipStreamclass. The following example shows how to set this attribute. <sessionState mode="SqlServer" sqlConnectionString="data source=dbserver;Initial Catalog=aspnetstate" allowCustomSqlDatabase="true" compressionEnabled="true" /> ASP.NET Web Forms Web Forms has been a core feature in ASP.NET since the release of ASP.NET 1.0. Many enhancements have been in this area for ASP.NET 4, such as the following: The ability to set meta tags. More control over view state. Support for recently introduced browsers and devices. Easier ways to work with browser capabilities. Support for using ASP.NET routing with Web Forms. More control over generated IDs. The ability to persist selected rows in data controls. More control over rendered HTML in the FormView and ListView controls. Filtering support for data source controls. Enhanced support for Web standards and accessibility Setting Meta Tags with the Page.MetaKeywords and Page.MetaDescription Properties Two properties have been added to the Page class: MetaKeywords and MetaDescription. These two properties represent corresponding meta tags in the HTML rendered for a page, as shown in the following example: <head id="Head1" runat="server"> <title>Untitled Page</title> <meta name="keywords" content="keyword1, keyword2' /> <meta name="description" content="Description of my page" /> </head> These two properties work like the Title property does, and they can be set in the @ Page directive. For more information, see Page.MetaKeywords and Page.MetaDescription. Enabling View State for Individual Controls A new property has been added to the Control class: ViewStateMode. You can use this property to disable view state for all controls on a page except those for which you explicitly enable view state. View state data is included in a page's HTML and increases the amount of time it takes to send a page to the client and post it back. Storing more view state than is necessary can cause significant decrease in performance. In earlier versions of ASP.NET, you could reduce the impact of view state on a page's performance by disabling view state for specific controls. But sometimes it is easier to enable view state for a few controls that need it instead of disabling it for many that do not need it. For more information, see Control.ViewStateMode. Support for Recently Introduced Browsers and Devices ASP.NET includes a feature that is named browser capabilities that lets you determine the capabilities of the browser that a user is using. Browser capabilities are represented by the HttpBrowserCapabilities object which is stored in the HttpRequest.Browser property. Information about a particular browser's capabilities is defined by a browser definition file. In ASP.NET 4, these browser definition files have been updated to contain information about recently introduced browsers and devices such as Google Chrome, Research in Motion BlackBerry smart phones, and Apple iPhone. Existing browser definition files have also been updated. For more information, see How to: Upgrade an ASP.NET Web Application to ASP.NET 4 and ASP.NET Web Server Controls and Browser Capabilities. The browser definition files that are included with ASP.NET 4 are shown in the following list: •blackberry.browser •chrome.browser •Default.browser •firefox.browser •gateway.browser •generic.browser •ie.browser •iemobile.browser •iphone.browser •opera.browser •safari.browser A New Way to Define Browser Capabilities ASP.NET 4 includes a new feature referred to as browser capabilities providers. As the name suggests, this lets you build a provider that in turn lets you write custom code to determine browser capabilities. In ASP.NET version 3.5 Service Pack 1, you define browser capabilities in an XML file. This file resides in a machine-level folder or an application-level folder. Most developers do not need to customize these files, but for those who do, the provider approach can be easier than dealing with complex XML syntax. The provider approach makes it possible to simplify the process by implementing a common browser definition syntax, or a database that contains up-to-date browser definitions, or even a Web service for such a database. For more information about the new browser capabilities provider, see the What's New for ASP.NET 4 White Paper. Routing in ASP.NET 4 ASP.NET 4 adds built-in support for routing with Web Forms. Routing is a feature that was introduced with ASP.NET 3.5 SP1 and lets you configure an application to use URLs that are meaningful to users and to search engines because they do not have to specify physical file names. This can make your site more user-friendly and your site content more discoverable by search engines. For example, the URL for a page that displays product categories in your application might look like the following example: http://website/products.aspx?categoryid=12 By using routing, you can use the following URL to render the same information: http://website/products/software The second URL lets the user know what to expect and can result in significantly improved rankings in search engine results. the new features include the following: The PageRouteHandler class is a simple HTTP handler that you use when you define routes. You no longer have to write a custom route handler. The HttpRequest.RequestContext and Page.RouteData properties make it easier to access information that is passed in URL parameters. The RouteUrl expression provides a simple way to create a routed URL in markup. The RouteValue expression provides a simple way to extract URL parameter values in markup. The RouteParameter class makes it easier to pass URL parameter values to a query for a data source control (similar to FormParameter). You no longer have to change the Web.config file to enable routing. For more information about routing, see the following topics: ASP.NET Routing Walkthrough: Using ASP.NET Routing in a Web Forms Application How to: Define Routes for Web Forms Applications How to: Construct URLs from Routes How to: Access URL Parameters in a Routed Page Setting Client IDs The new ClientIDMode property makes it easier to write client script that references HTML elements rendered for server controls. Increasing use of Microsoft Ajax makes the need to do this more common. For example, you may have a data control that renders a long list of products with prices and you want to use client script to make a Web service call and update individual prices in the list as they change without refreshing the entire page. Typically you get a reference to an HTML element in client script by using the document.GetElementById method. You pass to this method the value of the id attribute of the HTML element you want to reference. In the case of elements that are rendered for ASP.NET server controls earlier versions of ASP.NET could make this difficult or impossible. You were not always able to predict what id values ASP.NET would generate, or ASP.NET could generate very long id values. The problem was especially difficult for data controls that would generate multiple rows for a single instance of the control in your markup. ASP.NET 4 adds two new algorithms for generating id attributes. These algorithms can generate id attributes that are easier to work with in client script because they are more predictable and that are easier to work with because they are simpler. For more information about how to use the new algorithms, see the following topics: ASP.NET Web Server Control Identification Walkthrough: Making Data-Bound Controls Easier to Access from JavaScript Walkthrough: Making Controls Located in Web User Controls Easier to Access from JavaScript How to: Access Controls from JavaScript by ID Persisting Row Selection in Data Controls The GridView and ListView controls enable users to select a row. In previous versions of ASP.NET, row selection was based on the row index on the page. For example, if you select the third item on page 1 and then move to page 2, the third item on page 2 is selected. In most cases, is more desirable not to select any rows on page 2. ASP.NET 4 supports Persisted Selection, a new feature that was initially supported only in Dynamic Data projects in the .NET Framework 3.5 SP1. When this feature is enabled, the selected item is based on the row data key. This means that if you select the third row on page 1 and move to page 2, nothing is selected on page 2. When you move back to page 1, the third row is still selected. This is a much more natural behavior than the behavior in earlier versions of ASP.NET. Persisted selection is now supported for the GridView and ListView controls in all projects. You can enable this feature in the GridView control, for example, by setting the EnablePersistedSelection property, as shown in the following example: <asp:GridView id="GridView2" runat="server" PersistedSelection="true"> </asp:GridView> FormView Control Enhancements The FormView control is enhanced to make it easier to style the content of the control with CSS. In previous versions of ASP.NET, the FormView control rendered it contents using an item template. This made styling more difficult in the markup because unexpected table row and table cell tags were rendered by the control. The FormView control supports RenderOuterTable, a property in ASP.NET 4. When this property is set to false, as show in the following example, the table tags are not rendered. This makes it easier to apply CSS style to the contents of the control. <asp:FormView ID="FormView1" runat="server" RenderTable="false"> For more information, see FormView Web Server Control Overview. ListView Control Enhancements The ListView control, which was introduced in ASP.NET 3.5, has all the functionality of the GridView control while giving you complete control over the output. This control has been made easier to use in ASP.NET 4. The earlier version of the control required that you specify a layout template that contained a server control with a known ID. The following markup shows a typical example of how to use the ListView control in ASP.NET 3.5. <asp:ListView ID="ListView1" runat="server"> <LayoutTemplate> <asp:PlaceHolder ID="ItemPlaceHolder" runat="server"></asp:PlaceHolder> </LayoutTemplate> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> In ASP.NET 4, the ListView control does not require a layout template. The markup shown in the previous example can be replaced with the following markup: <asp:ListView ID="ListView1" runat="server"> <ItemTemplate> <% Eval("LastName")%> </ItemTemplate> </asp:ListView> For more information, see ListView Web Server Control Overview. Filtering Data with the QueryExtender Control A very common task for developers who create data-driven Web pages is to filter data. This traditionally has been performed by building Where clauses in data source controls. This approach can be complicated, and in some cases the Where syntax does not let you take advantage of the full functionality of the underlying database. To make filtering easier, a new QueryExtender control has been added in ASP.NET 4. This control can be added to EntityDataSource or LinqDataSource controls in order to filter the data returned by these controls. Because the QueryExtender control relies on LINQ, but you do not to need to know how to write LINQ queries to use the query extender. The QueryExtender control supports a variety of filter options. The following lists QueryExtender filter options. Term Definition SearchExpression Searches a field or fields for string values and compares them to a specified string value. RangeExpression Searches a field or fields for values in a range specified by a pair of values. PropertyExpression Compares a specified value to a property value in a field. If the expression evaluates to true, the data that is being examined is returned. OrderByExpression Sorts data by a specified column and sort direction. CustomExpression Calls a function that defines custom filter in the page. For more information, see QueryExtenderQueryExtender Web Server Control Overview. Enhanced Support for Web Standards and Accessibility Earlier versions of ASP.NET controls sometimes render markup that does not conform to HTML, XHTML, or accessibility standards. ASP.NET 4 eliminates most of these exceptions. For details about how the HTML that is rendered by each control meets accessibility standards, see ASP.NET Controls and Accessibility. CSS for Controls that Can be Disabled In ASP.NET 3.5, when a control is disabled (see WebControl.Enabled), a disabled attribute is added to the rendered HTML element. For example, the following markup creates a Label control that is disabled: <asp:Label id="Label1" runat="server"   Text="Test" Enabled="false" /> In ASP.NET 3.5, the previous control settings generate the following HTML: <span id="Label1" disabled="disabled">Test</span> In HTML 4.01, the disabled attribute is not considered valid on span elements. It is valid only on input elements because it specifies that they cannot be accessed. On display-only elements such as span elements, browsers typically support rendering for a disabled appearance, but a Web page that relies on this non-standard behavior is not robust according to accessibility standards. For display-only elements, you should use CSS to indicate a disabled visual appearance. Therefore, by default ASP.NET 4 generates the following HTML for the control settings shown previously: <span id="Label1" class="aspNetDisabled">Test</span> You can change the value of the class attribute that is rendered by default when a control is disabled by setting the DisabledCssClass property. CSS for Validation Controls In ASP.NET 3.5, validation controls render a default color of red as an inline style. For example, the following markup creates a RequiredFieldValidator control: <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server"   ErrorMessage="Required Field" ControlToValidate="RadioButtonList1" /> ASP.NET 3.5 renders the following HTML for the validator control: <span id="RequiredFieldValidator1"   style="color:Red;visibility:hidden;">RequiredFieldValidator</span> By default, ASP.NET 4 does not render an inline style to set the color to red. An inline style is used only to hide or show the validator, as shown in the following example: <span id="RequiredFieldValidator1"   style"visibility:hidden;">RequiredFieldValidator</span> Therefore, ASP.NET 4 does not automatically show error messages in red. For information about how to use CSS to specify a visual style for a validation control, see Validating User Input in ASP.NET Web Pages. CSS for the Hidden Fields Div Element ASP.NET uses hidden fields to store state information such as view state and control state. These hidden fields are contained by a div element. In ASP.NET 3.5, this div element does not have a class attribute or an id attribute. Therefore, CSS rules that affect all div elements could unintentionally cause this div to be visible. To avoid this problem, ASP.NET 4 renders the div element for hidden fields with a CSS class that you can use to differentiate the hidden fields div from others. The new classvalue is shown in the following example: <div class="aspNetHidden"> CSS for the Table, Image, and ImageButton Controls By default, in ASP.NET 3.5, some controls set the border attribute of rendered HTML to zero (0). The following example shows HTML that is generated by the Table control in ASP.NET 3.5: <table id="Table2" border="0"> The Image control and the ImageButton control also do this. Because this is not necessary and provides visual formatting information that should be provided by using CSS, the attribute is not generated in ASP.NET 4. CSS for the UpdatePanel and UpdateProgress Controls In ASP.NET 3.5, the UpdatePanel and UpdateProgress controls do not support expando attributes. This makes it impossible to set a CSS class on the HTMLelements that they render. In ASP.NET 4 these controls have been changed to accept expando attributes, as shown in the following example: <asp:UpdatePanel runat="server" class="myStyle"> </asp:UpdatePanel> The following HTML is rendered for this markup: <div id="ctl00_MainContent_UpdatePanel1" class="expandoclass"> </div> Eliminating Unnecessary Outer Tables In ASP.NET 3.5, the HTML that is rendered for the following controls is wrapped in a table element whose purpose is to apply inline styles to the entire control: FormView Login PasswordRecovery ChangePassword If you use templates to customize the appearance of these controls, you can specify CSS styles in the markup that you provide in the templates. In that case, no extra outer table is required. In ASP.NET 4, you can prevent the table from being rendered by setting the new RenderOuterTable property to false. Layout Templates for Wizard Controls In ASP.NET 3.5, the Wizard and CreateUserWizard controls generate an HTML table element that is used for visual formatting. In ASP.NET 4 you can use a LayoutTemplate element to specify the layout. If you do this, the HTML table element is not generated. In the template, you create placeholder controls to indicate where items should be dynamically inserted into the control. (This is similar to how the template model for the ListView control works.) For more information, see the Wizard.LayoutTemplate property. New HTML Formatting Options for the CheckBoxList and RadioButtonList Controls ASP.NET 3.5 uses HTML table elements to format the output for the CheckBoxList and RadioButtonList controls. To provide an alternative that does not use tables for visual formatting, ASP.NET 4 adds two new options to the RepeatLayout enumeration: UnorderedList. This option causes the HTML output to be formatted by using ul and li elements instead of a table. OrderedList. This option causes the HTML output to be formatted by using ol and li elements instead of a table. For examples of HTML that is rendered for the new options, see the RepeatLayout enumeration. Header and Footer Elements for the Table Control In ASP.NET 3.5, the Table control can be configured to render thead and tfoot elements by setting the TableSection property of the TableHeaderRow class and the TableFooterRow class. In ASP.NET 4 these properties are set to the appropriate values by default. CSS and ARIA Support for the Menu Control In ASP.NET 3.5, the Menu control uses HTML table elements for visual formatting, and in some configurations it is not keyboard-accessible. ASP.NET 4 addresses these problems and improves accessibility in the following ways: The generated HTML is structured as an unordered list (ul and li elements). CSS is used for visual formatting. The menu behaves in accordance with ARIA standards for keyboard access. You can use arrow keys to navigate menu items. (For information about ARIA, see Accessibility in Visual Studio and ASP.NET.) ARIA role and property attributes are added to the generated HTML. (Attributes are added by using JavaScript instead of included in the HTML, to avoid generating HTML that would cause markup validation errors.) Styles for the Menu control are rendered in a style block at the top of the page, instead of inline with the rendered HTML elements. If you want to use a separate CSS file so that you can modify the menu styles, you can set the Menu control's new IncludeStyleBlock property to false, in which case the style block is not generated. Valid XHTML for the HtmlForm Control In ASP.NET 3.5, the HtmlForm control (which is created implicitly by the <form runat="server"> tag) renders an HTML form element that has both name and id attributes. The name attribute is deprecated in XHTML 1.1. Therefore, this control does not render the name attribute in ASP.NET 4. Maintaining Backward Compatibility in Control Rendering An existing ASP.NET Web site might have code in it that assumes that controls are rendering HTML the way they do in ASP.NET 3.5. To avoid causing backward compatibility problems when you upgrade the site to ASP.NET 4, you can have ASP.NET continue to generate HTML the way it does in ASP.NET 3.5 after you upgrade the site. To do so, you can set the controlRenderingCompatibilityVersion attribute of the pages element to "3.5" in the Web.config file of an ASP.NET 4 Web site, as shown in the following example: <system.web>   <pages controlRenderingCompatibilityVersion="3.5"/> </system.web> If this setting is omitted, the default value is the same as the version of ASP.NET that the Web site targets. (For information about multi-targeting in ASP.NET, see .NET Framework Multi-Targeting for ASP.NET Web Projects.) ASP.NET MVC ASP.NET MVC helps Web developers build compelling standards-based Web sites that are easy to maintain because it decreases the dependency among application layers by using the Model-View-Controller (MVC) pattern. MVC provides complete control over the page markup. It also improves testability by inherently supporting Test Driven Development (TDD). Web sites created using ASP.NET MVC have a modular architecture. This allows members of a team to work independently on the various modules and can be used to improve collaboration. For example, developers can work on the model and controller layers (data and logic), while the designer work on the view (presentation). For tutorials, walkthroughs, conceptual content, code samples, and a complete API reference, see ASP.NET MVC 2. Dynamic Data Dynamic Data was introduced in the .NET Framework 3.5 SP1 release in mid-2008. This feature provides many enhancements for creating data-driven applications, such as the following: A RAD experience for quickly building a data-driven Web site. Automatic validation that is based on constraints defined in the data model. The ability to easily change the markup that is generated for fields in the GridView and DetailsView controls by using field templates that are part of your Dynamic Data project. For ASP.NET 4, Dynamic Data has been enhanced to give developers even more power for quickly building data-driven Web sites. For more information, see ASP.NET Dynamic Data Content Map. Enabling Dynamic Data for Individual Data-Bound Controls in Existing Web Applications You can use Dynamic Data features in existing ASP.NET Web applications that do not use scaffolding by enabling Dynamic Data for individual data-bound controls. Dynamic Data provides the presentation and data layer support for rendering these controls. When you enable Dynamic Data for data-bound controls, you get the following benefits: Setting default values for data fields. Dynamic Data enables you to provide default values at run time for fields in a data control. Interacting with the database without creating and registering a data model. Automatically validating the data that is entered by the user without writing any code. For more information, see Walkthrough: Enabling Dynamic Data in ASP.NET Data-Bound Controls. New Field Templates for URLs and E-mail Addresses ASP.NET 4 introduces two new built-in field templates, EmailAddress.ascx and Url.ascx. These templates are used for fields that are marked as EmailAddress or Url using the DataTypeAttribute attribute. For EmailAddress objects, the field is displayed as a hyperlink that is created by using the mailto: protocol. When users click the link, it opens the user's e-mail client and creates a skeleton message. Objects typed as Url are displayed as ordinary hyperlinks. The following example shows how to mark fields. [DataType(DataType.EmailAddress)] public object HomeEmail { get; set; } [DataType(DataType.Url)] public object Website { get; set; } Creating Links with the DynamicHyperLink Control Dynamic Data uses the new routing feature that was added in the .NET Framework 3.5 SP1 to control the URLs that users see when they access the Web site. The new DynamicHyperLink control makes it easy to build links to pages in a Dynamic Data site. For information, see How to: Create Table Action Links in Dynamic Data Support for Inheritance in the Data Model Both the ADO.NET Entity Framework and LINQ to SQL support inheritance in their data models. An example of this might be a database that has an InsurancePolicy table. It might also contain CarPolicy and HousePolicy tables that have the same fields as InsurancePolicy and then add more fields. Dynamic Data has been modified to understand inherited objects in the data model and to support scaffolding for the inherited tables. For more information, see Walkthrough: Mapping Table-per-Hierarchy Inheritance in Dynamic Data. Support for Many-to-Many Relationships (Entity Framework Only) The Entity Framework has rich support for many-to-many relationships between tables, which is implemented by exposing the relationship as a collection on an Entity object. New field templates (ManyToMany.ascx and ManyToMany_Edit.ascx) have been added to provide support for displaying and editing data that is involved in many-to-many relationships. For more information, see Working with Many-to-Many Data Relationships in Dynamic Data. New Attributes to Control Display and Support Enumerations The DisplayAttribute has been added to give you additional control over how fields are displayed. The DisplayNameAttribute attribute in earlier versions of Dynamic Data enabled you to change the name that is used as a caption for a field. The new DisplayAttribute class lets you specify more options for displaying a field, such as the order in which a field is displayed and whether a field will be used as a filter. The attribute also provides independent control of the name that is used for the labels in a GridView control, the name that is used in a DetailsView control, the help text for the field, and the watermark used for the field (if the field accepts text input). The EnumDataTypeAttribute class has been added to let you map fields to enumerations. When you apply this attribute to a field, you specify an enumeration type. Dynamic Data uses the new Enumeration.ascx field template to create UI for displaying and editing enumeration values. The template maps the values from the database to the names in the enumeration. Enhanced Support for Filters Dynamic Data 1.0 had built-in filters for Boolean columns and foreign-key columns. The filters did not let you specify the order in which they were displayed. The new DisplayAttribute attribute addresses this by giving you control over whether a column appears as a filter and in what order it will be displayed. An additional enhancement is that filtering support has been rewritten to use the new QueryExtender feature of Web Forms. This lets you create filters without requiring knowledge of the data source control that the filters will be used with. Along with these extensions, filters have also been turned into template controls, which lets you add new ones. Finally, the DisplayAttribute class mentioned earlier allows the default filter to be overridden, in the same way that UIHint allows the default field template for a column to be overridden. For more information, see Walkthrough: Filtering Rows in Tables That Have a Parent-Child Relationship and QueryableFilterRepeater. ASP.NET Chart Control The ASP.NET chart server control enables you to create ASP.NET pages applications that have simple, intuitive charts for complex statistical or financial analysis. The chart control supports the following features: Data series, chart areas, axes, legends, labels, titles, and more. Data binding. Data manipulation, such as copying, splitting, merging, alignment, grouping, sorting, searching, and filtering. Statistical formulas and financial formulas. Advanced chart appearance, such as 3-D, anti-aliasing, lighting, and perspective. Events and customizations. Interactivity and Microsoft Ajax. Support for the Ajax Content Delivery Network (CDN), which provides an optimized way for you to add Microsoft Ajax Library and jQuery scripts to your Web applications. For more information, see Chart Web Server Control Overview. Visual Web Developer Enhancements The following sections provide information about enhancements and new features in Visual Studio 2010 and Visual Web Developer Express. The Web page designer in Visual Studio 2010 has been enhanced for better CSS compatibility, includes additional support for HTML and ASP.NET markup snippets, and features a redesigned version of IntelliSense for JScript. Improved CSS Compatibility The Visual Web Developer designer in Visual Studio 2010 has been updated to improve CSS 2.1 standards compliance. The designer better preserves HTML source code and is more robust than in previous versions of Visual Studio. HTML and JScript Snippets In the HTML editor, IntelliSense auto-completes tag names. The IntelliSense Snippets feature auto-completes whole tags and more. In Visual Studio 2010, IntelliSense snippets are supported for JScript, alongside C# and Visual Basic, which were supported in earlier versions of Visual Studio. Visual Studio 2010 includes over 200 snippets that help you auto-complete common ASP.NET and HTML tags, including required attributes (such as runat="server") and common attributes specific to a tag (such as ID, DataSourceID, ControlToValidate, and Text). You can download additional snippets, or you can write your own snippets that encapsulate the blocks of markup that you or your team use for common tasks. For more information on HTML snippets, see Walkthrough: Using HTML Snippets. JScript IntelliSense Enhancements In Visual 2010, JScript IntelliSense has been redesigned to provide an even richer editing experience. IntelliSense now recognizes objects that have been dynamically generated by methods such as registerNamespace and by similar techniques used by other JavaScript frameworks. Performance has been improved to analyze large libraries of script and to display IntelliSense with little or no processing delay. Compatibility has been significantly increased to support almost all third-party libraries and to support diverse coding styles. Documentation comments are now parsed as you type and are immediately leveraged by IntelliSense. Web Application Deployment with Visual Studio 2010 For Web application projects, Visual Studio now provides tools that work with the IIS Web Deployment Tool (Web Deploy) to automate many processes that had to be done manually in earlier versions of ASP.NET. For example, the following tasks can now be automated: Creating an IIS application on the destination computer and configuring IIS settings. Copying files to the destination computer. Changing Web.config settings that must be different in the destination environment. Propagating changes to data or data structures in SQL Server databases that are used by the Web application. For more information about Web application deployment, see ASP.NET Deployment Content Map. Enhancements to ASP.NET Multi-Targeting ASP.NET 4 adds new features to the multi-targeting feature to make it easier to work with projects that target earlier versions of the .NET Framework. Multi-targeting was introduced in ASP.NET 3.5 to enable you to use the latest version of Visual Studio without having to upgrade existing Web sites or Web services to the latest version of the .NET Framework. In Visual Studio 2008, when you work with a project targeted for an earlier version of the .NET Framework, most features of the development environment adapt to the targeted version. However, IntelliSense displays language features that are available in the current version, and property windows display properties available in the current version. In Visual Studio 2010, only language features and properties available in the targeted version of the .NET Framework are shown. For more information about multi-targeting, see the following topics: .NET Framework Multi-Targeting for ASP.NET Web Projects ASP.NET Side-by-Side Execution Overview How to: Host Web Applications That Use Different Versions of the .NET Framework on the Same Server How to: Deploy Web Site Projects Targeted for Earlier Versions of the .NET Framework

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  • Building applications with WPF, MVVM and Prism(aka CAG)

    - by skjagini
    In this article I am going to walk through an application using WPF and Prism (aka composite application guidance, CAG) which simulates engaging a taxi (cab).  The rules are simple, the app would have3 screens A login screen to authenticate the user An information screen. A screen to engage the cab and roam around and calculating the total fare Metered Rate of Fare The meter is required to be engaged when a cab is occupied by anyone $3.00 upon entry $0.35 for each additional unit The unit fare is: one-fifth of a mile, when the cab is traveling at 6 miles an hour or more; or 60 seconds when not in motion or traveling at less than 12 miles per hour. Night surcharge of $.50 after 8:00 PM & before 6:00 AM Peak hour Weekday Surcharge of $1.00 Monday - Friday after 4:00 PM & before 8:00 PM New York State Tax Surcharge of $.50 per ride. Example: Friday (2010-10-08) 5:30pm Start at Lexington Ave & E 57th St End at Irving Pl & E 15th St Start = $3.00 Travels 2 miles at less than 6 mph for 15 minutes = $3.50 Travels at more than 12 mph for 5 minutes = $1.75 Peak hour Weekday Surcharge = $1.00 (ride started at 5:30 pm) New York State Tax Surcharge = $0.50 Before we dive into the app, I would like to give brief description about the framework.  If you want to jump on to the source code, scroll all the way to the end of the post. MVVM MVVM pattern is in no way related to the usage of PRISM in your application and should be considered if you are using WPF irrespective of PRISM or not. Lets say you are not familiar with MVVM, your typical UI would involve adding some UI controls like text boxes, a button, double clicking on the button,  generating event handler, calling a method from business layer and updating the user interface, it works most of the time for developing small scale applications. The problem with this approach is that there is some amount of code specific to business logic wrapped in UI specific code which is hard to unit test it, mock it and MVVM helps to solve the exact problem. MVVM stands for Model(M) – View(V) – ViewModel(VM),  based on the interactions with in the three parties it should be called VVMM,  MVVM sounds more like MVC (Model-View-Controller) so the name. Why it should be called VVMM: View – View Model - Model WPF allows to create user interfaces using XAML and MVVM takes it to the next level by allowing complete separation of user interface and business logic. In WPF each view will have a property, DataContext when set to an instance of a class (which happens to be your view model) provides the data the view is interested in, i.e., view interacts with view model and at the same time view model interacts with view through DataContext. Sujith, if view and view model are interacting directly with each other how does MVVM is helping me separation of concerns? Well, the catch is DataContext is of type Object, since it is of type object view doesn’t know exact type of view model allowing views and views models to be loosely coupled. View models aggregate data from models (data access layer, services, etc) and make it available for views through properties, methods etc, i.e., View Models interact with Models. PRISM Prism is provided by Microsoft Patterns and Practices team and it can be downloaded from codeplex for source code,  samples and documentation on msdn.  The name composite implies, to compose user interface from different modules (views) without direct dependencies on each other, again allowing  loosely coupled development. Well Sujith, I can already do that with user controls, why shall I learn another framework?  That’s correct, you can decouple using user controls, but you still have to manage some amount of coupling, like how to do you communicate between the controls, how do you subscribe/unsubscribe, loading/unloading views dynamically. Prism is not a replacement for user controls, provides the following features which greatly help in designing the composite applications. Dependency Injection (DI)/ Inversion of Control (IoC) Modules Regions Event Aggregator  Commands Simply put, MVVM helps building a single view and Prism helps building an application using the views There are other open source alternatives to Prism, like MVVMLight, Cinch, take a look at them as well. Lets dig into the source code.  1. Solution The solution is made of the following projects Framework: Holds the common functionality in building applications using WPF and Prism TaxiClient: Start up project, boot strapping and app styling TaxiCommon: Helps with the business logic TaxiModules: Holds the meat of the application with views and view models TaxiTests: To test the application 2. DI / IoC Dependency Injection (DI) as the name implies refers to injecting dependencies and Inversion of Control (IoC) means the calling code has no direct control on the dependencies, opposite of normal way of programming where dependencies are passed by caller, i.e inversion; aside from some differences in terminology the concept is same in both the cases. The idea behind DI/IoC pattern is to reduce the amount of direct coupling between different components of the application, the higher the dependency the more tightly coupled the application resulting in code which is hard to modify, unit test and mock.  Initializing Dependency Injection through BootStrapper TaxiClient is the starting project of the solution and App (App.xaml)  is the starting class that gets called when you run the application. From the App’s OnStartup method we will invoke BootStrapper.   namespace TaxiClient { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : Application { protected override void OnStartup(StartupEventArgs e) { base.OnStartup(e);   (new BootStrapper()).Run(); } } } BootStrapper is your contact point for initializing the application including dependency injection, creating Shell and other frameworks. We are going to use Unity for DI and there are lot of open source DI frameworks like Spring.Net, StructureMap etc with different feature set  and you can choose a framework based on your preferences. Note that Prism comes with in built support for Unity, for example we are deriving from UnityBootStrapper in our case and for any other DI framework you have to extend the Prism appropriately   namespace TaxiClient { public class BootStrapper: UnityBootstrapper { protected override IModuleCatalog CreateModuleCatalog() { return new ConfigurationModuleCatalog(); } protected override DependencyObject CreateShell() { Framework.FrameworkBootStrapper.Run(Container, Application.Current.Dispatcher);   Shell shell = new Shell(); shell.ResizeMode = ResizeMode.NoResize; shell.Show();   return shell; } } } Lets take a look into  FrameworkBootStrapper to check out how to register with unity container. namespace Framework { public class FrameworkBootStrapper { public static void Run(IUnityContainer container, Dispatcher dispatcher) { UIDispatcher uiDispatcher = new UIDispatcher(dispatcher); container.RegisterInstance<IDispatcherService>(uiDispatcher);   container.RegisterType<IInjectSingleViewService, InjectSingleViewService>( new ContainerControlledLifetimeManager());   . . . } } } In the above code we are registering two components with unity container. You shall observe that we are following two different approaches, RegisterInstance and RegisterType.  With RegisterInstance we are registering an existing instance and the same instance will be returned for every request made for IDispatcherService   and with RegisterType we are requesting unity container to create an instance for us when required, i.e., when I request for an instance for IInjectSingleViewService, unity will create/return an instance of InjectSingleViewService class and with RegisterType we can configure the life time of the instance being created. With ContaienrControllerLifetimeManager, the unity container caches the instance and reuses for any subsequent requests, without recreating a new instance. Lets take a look into FareViewModel.cs and it’s constructor. The constructor takes one parameter IEventAggregator and if you try to find all references in your solution for IEventAggregator, you will not find a single location where an instance of EventAggregator is passed directly to the constructor. The compiler still finds an instance and works fine because Prism is already configured when used with Unity container to return an instance of EventAggregator when requested for IEventAggregator and in this particular case it is called constructor injection. public class FareViewModel:ObservableBase, IDataErrorInfo { ... private IEventAggregator _eventAggregator;   public FareViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; InitializePropertyNames(); InitializeModel(); PropertyChanged += OnPropertyChanged; } ... 3. Shell Shells are very similar in operation to Master Pages in asp.net or MDI in Windows Forms. And shells contain regions which display the views, you can have as many regions as you wish in a given view. You can also nest regions. i.e, one region can load a view which in itself may contain other regions. We have to create a shell at the start of the application and are doing it by overriding CreateShell method from BootStrapper From the following Shell.xaml you shall notice that we have two content controls with Region names as ‘MenuRegion’ and ‘MainRegion’.  The idea here is that you can inject any user controls into the regions dynamically, i.e., a Menu User Control for MenuRegion and based on the user action you can load appropriate view into MainRegion.    <Window x:Class="TaxiClient.Shell" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Regions="clr-namespace:Microsoft.Practices.Prism.Regions;assembly=Microsoft.Practices.Prism" Title="Taxi" Height="370" Width="800"> <Grid Margin="2"> <ContentControl Regions:RegionManager.RegionName="MenuRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" />   <ContentControl Grid.Row="1" Regions:RegionManager.RegionName="MainRegion" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" /> <!--<Border Grid.ColumnSpan="2" BorderThickness="2" CornerRadius="3" BorderBrush="LightBlue" />-->   </Grid> </Window> 4. Modules Prism provides the ability to build composite applications and modules play an important role in it. For example if you are building a Mortgage Loan Processor application with 3 components, i.e. customer’s credit history,  existing mortgages, new home/loan information; and consider that the customer’s credit history component involves gathering data about his/her address, background information, job details etc. The idea here using Prism modules is to separate the implementation of these 3 components into their own visual studio projects allowing to build components with no dependency on each other and independently. If we need to add another component to the application, the component can be developed by in house team or some other team in the organization by starting with a new Visual Studio project and adding to the solution at the run time with very little knowledge about the application. Prism modules are defined by implementing the IModule interface and each visual studio project to be considered as a module should implement the IModule interface.  From the BootStrapper.cs you shall observe that we are overriding the method by returning a ConfiguratingModuleCatalog which returns the modules that are registered for the application using the app.config file  and you can also add module using code. Lets take a look into configuration file.   <?xml version="1.0"?> <configuration> <configSections> <section name="modules" type="Microsoft.Practices.Prism.Modularity.ModulesConfigurationSection, Microsoft.Practices.Prism"/> </configSections> <modules> <module assemblyFile="TaxiModules.dll" moduleType="TaxiModules.ModuleInitializer, TaxiModules" moduleName="TaxiModules"/> </modules> </configuration> Here we are adding TaxiModules project to our solution and TaxiModules.ModuleInitializer implements IModule interface   5. Module Mapper With Prism modules you can dynamically add or remove modules from the regions, apart from that Prism also provides API to control adding/removing the views from a region within the same module. Taxi Information Screen: Engage the Taxi Screen: The sample application has two screens, ‘Taxi Information’ and ‘Engage the Taxi’ and they both reside in same module, TaxiModules. ‘Engage the Taxi’ is again made of two user controls, FareView on the left and TotalView on the right. We have created a Shell with two regions, MenuRegion and MainRegion with menu loaded into MenuRegion. We can create a wrapper user control called EngageTheTaxi made of FareView and TotalView and load either TaxiInfo or EngageTheTaxi into MainRegion based on the user action. Though it will work it tightly binds the user controls and for every combination of user controls, we need to create a dummy wrapper control to contain them. Instead we can apply the principles we learned so far from Shell/regions and introduce another template (LeftAndRightRegionView.xaml) made of two regions Region1 (left) and Region2 (right) and load  FareView and TotalView dynamically.  To help with loading of the views dynamically I have introduce an helper an interface, IInjectSingleViewService,  idea suggested by Mike Taulty, a must read blog for .Net developers. using System; using System.Collections.Generic; using System.ComponentModel;   namespace Framework.PresentationUtility.Navigation {   public interface IInjectSingleViewService : INotifyPropertyChanged { IEnumerable<CommandViewDefinition> Commands { get; } IEnumerable<ModuleViewDefinition> Modules { get; }   void RegisterViewForRegion(string commandName, string viewName, string regionName, Type viewType); void ClearViewFromRegion(string viewName, string regionName); void RegisterModule(string moduleName, IList<ModuleMapper> moduleMappers); } } The Interface declares three methods to work with views: RegisterViewForRegion: Registers a view with a particular region. You can register multiple views and their regions under one command.  When this particular command is invoked all the views registered under it will be loaded into their regions. ClearViewFromRegion: To unload a specific view from a region. RegisterModule: The idea is when a command is invoked you can load the UI with set of controls in their default position and based on the user interaction, you can load different contols in to different regions on the fly.  And it is supported ModuleViewDefinition and ModuleMappers as shown below. namespace Framework.PresentationUtility.Navigation { public class ModuleViewDefinition { public string ModuleName { get; set; } public IList<ModuleMapper> ModuleMappers; public ICommand Command { get; set; } }   public class ModuleMapper { public string ViewName { get; set; } public string RegionName { get; set; } public Type ViewType { get; set; } } } 6. Event Aggregator Prism event aggregator enables messaging between components as in Observable pattern, Notifier notifies the Observer which receives notification it is interested in. When it comes to Observable pattern, Observer has to unsubscribes for notifications when it no longer interested in notifications, which allows the Notifier to remove the Observer’s reference from it’s local cache. Though .Net has managed garbage collection it cannot remove inactive the instances referenced by an active instance resulting in memory leak, keeping the Observers in memory as long as Notifier stays in memory.  Developers have to be very careful to unsubscribe when necessary and it often gets overlooked, to overcome these problems Prism Event Aggregator uses weak references to cache the reference (Observer in this case)  and releases the reference (memory) once the instance goes out of scope. Using event aggregator is very simple, declare a generic type of CompositePresenationEvent by inheriting from it. using Microsoft.Practices.Prism.Events; using TaxiCommon.BAO;   namespace TaxiCommon.CompositeEvents { public class TaxiOnMoveEvent:CompositePresentationEvent<TaxiOnMove> { } }   TaxiOnMove.cs includes the properties which we want to exchange between the parties, FareView and TotalView. using System;   namespace TaxiCommon.BAO { public class TaxiOnMove { public TimeSpan MinutesAtTweleveMPH { get; set; } public double MilesAtSixMPH { get; set; } } }   Lets take a look into FareViewodel (Notifier) and how it raises the event.  Here we are raising the event by getting the event through GetEvent<..>() and publishing it with the payload private void OnAddMinutes(object obj) { TaxiOnMove payload = new TaxiOnMove(); if(MilesAtSixMPH != null) payload.MilesAtSixMPH = MilesAtSixMPH.Value; if(MinutesAtTweleveMPH != null) payload.MinutesAtTweleveMPH = new TimeSpan(0,0,MinutesAtTweleveMPH.Value,0);   _eventAggregator.GetEvent<TaxiOnMoveEvent>().Publish(payload); ResetMinutesAndMiles(); } And TotalViewModel(Observer) subscribes to notifications by getting the event through GetEvent<..>() namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { .... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator; ... }   private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>() .Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>() .Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>() .Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   ... private void OnTaxiMove(TaxiOnMove taxiOnMove) { OnMoveFare fare = new OnMoveFare(taxiOnMove); Fares.Add(fare); SetTotalFare(new []{fare}); }   .... 7. MVVM through example In this section we are going to look into MVVM implementation through example.  I have all the modules declared in a single project, TaxiModules, again it is not necessary to have them into one project. Once the user logs into the application, will be greeted with the ‘Engage the Taxi’ screen which is made of two user controls, FareView.xaml and TotalView.Xaml. As you can see from the solution explorer, each of them have their own code behind files and  ViewModel classes, FareViewMode.cs, TotalViewModel.cs Lets take a look in to the FareView and how it interacts with FareViewModel using MVVM implementation. FareView.xaml acts as a view and FareViewMode.cs is it’s view model. The FareView code behind class   namespace TaxiModules.Views { /// <summary> /// Interaction logic for FareView.xaml /// </summary> public partial class FareView : UserControl { public FareView(FareViewModel viewModel) { InitializeComponent(); this.Loaded += (s, e) => { this.DataContext = viewModel; }; } } } The FareView is bound to FareViewModel through the data context  and you shall observe that DataContext is of type Object, i.e. the FareView doesn’t really know the type of ViewModel (FareViewModel). This helps separation of View and ViewModel as View and ViewModel are independent of each other, you can bind FareView to FareViewModel2 as well and the application compiles just fine. Lets take a look into FareView xaml file  <UserControl x:Class="TaxiModules.Views.FareView" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:Toolkit="clr-namespace:Microsoft.Windows.Controls;assembly=WPFToolkit" xmlns:Commands="clr-namespace:Microsoft.Practices.Prism.Commands;assembly=Microsoft.Practices.Prism"> <Grid Margin="10" > ....   <Border Style="{DynamicResource innerBorder}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="11" Grid.ColumnSpan="2" Panel.ZIndex="1"/>   <Label Grid.Row="0" Content="Engage the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="1" Content="Select the State"/> <ComboBox Grid.Row="1" Grid.Column="1" ItemsSource="{Binding States}" Height="auto"> <ComboBox.ItemTemplate> <DataTemplate> <TextBlock Text="{Binding Name}"/> </DataTemplate> </ComboBox.ItemTemplate> <ComboBox.SelectedItem> <Binding Path="SelectedState" Mode="TwoWay"/> </ComboBox.SelectedItem> </ComboBox> <Label Grid.Row="2" Content="Select the Date of Entry"/> <Toolkit:DatePicker Grid.Row="2" Grid.Column="1" SelectedDate="{Binding DateOfEntry, ValidatesOnDataErrors=true}" /> <Label Grid.Row="3" Content="Enter time 24hr format"/> <TextBox Grid.Row="3" Grid.Column="1" Text="{Binding TimeOfEntry, TargetNullValue=''}"/> <Button Grid.Row="4" Grid.Column="1" Content="Start the Meter" Commands:Click.Command="{Binding StartMeterCommand}" />   <Label Grid.Row="5" Content="Run the Taxi" Style="{DynamicResource innerHeader}"/> <Label Grid.Row="6" Content="Number of Miles &lt;@6mph"/> <TextBox Grid.Row="6" Grid.Column="1" Text="{Binding MilesAtSixMPH, TargetNullValue='', ValidatesOnDataErrors=true}"/> <Label Grid.Row="7" Content="Number of Minutes @12mph"/> <TextBox Grid.Row="7" Grid.Column="1" Text="{Binding MinutesAtTweleveMPH, TargetNullValue=''}"/> <Button Grid.Row="8" Grid.Column="1" Content="Add Minutes and Miles " Commands:Click.Command="{Binding AddMinutesCommand}"/> <Label Grid.Row="9" Content="Other Operations" Style="{DynamicResource innerHeader}"/> <Button Grid.Row="10" Grid.Column="1" Content="Reset the Meter" Commands:Click.Command="{Binding ResetCommand}"/>   </Grid> </UserControl> The highlighted code from the above code shows data binding, for example ComboBox which displays list of states has it’s ItemsSource bound to States property, with DataTemplate bound to Name and SelectedItem  to SelectedState. You might be wondering what are all these properties and how it is able to bind to them.  The answer lies in data context, i.e., when you bound a control, WPF looks for data context on the root object (Grid in this case) and if it can’t find data context it will look into root’s root, i.e. FareView UserControl and it is bound to FareViewModel.  Each of those properties have be declared on the ViewModel for the View to bind correctly. To put simply, View is bound to ViewModel through data context of type object and every control that is bound on the View actually binds to the public property on the ViewModel. Lets look into the ViewModel code (the following code is not an exact copy of FareViewMode.cs, pasted relevant code for this section)   namespace TaxiModules.ViewModels { public class FareViewModel:ObservableBase, IDataErrorInfo { public List<USState> States { get { return USStates.StateList; } }   public USState SelectedState { get { return _selectedState; } set { _selectedState = value; RaisePropertyChanged(_selectedStatePropertyName); } }   public DateTime? DateOfEntry { get { return _dateOfEntry; } set { _dateOfEntry = value; RaisePropertyChanged(_dateOfEntryPropertyName); } }   public TimeSpan? TimeOfEntry { get { return _timeOfEntry; } set { _timeOfEntry = value; RaisePropertyChanged(_timeOfEntryPropertyName); } }   public double? MilesAtSixMPH { get { return _milesAtSixMPH; } set { _milesAtSixMPH = value; RaisePropertyChanged(_distanceAtSixMPHPropertyName); } }   public int? MinutesAtTweleveMPH { get { return _minutesAtTweleveMPH; } set { _minutesAtTweleveMPH = value; RaisePropertyChanged(_minutesAtTweleveMPHPropertyName); } }   public ICommand StartMeterCommand { get { if(_startMeterCommand == null) { _startMeterCommand = new DelegateCommand<object>(OnStartMeter, CanStartMeter); } return _startMeterCommand; } }   public ICommand AddMinutesCommand { get { if(_addMinutesCommand == null) { _addMinutesCommand = new DelegateCommand<object>(OnAddMinutes, CanAddMinutes); } return _addMinutesCommand; } }   public ICommand ResetCommand { get { if(_resetCommand == null) { _resetCommand = new DelegateCommand<object>(OnResetCommand); } return _resetCommand; } }   } private void OnStartMeter(object obj) { _eventAggregator.GetEvent<TaxiStartedEvent>().Publish( new TaxiStarted() { EngagedOn = DateOfEntry.Value.Date + TimeOfEntry.Value, EngagedState = SelectedState.Value });   _isMeterStarted = true; OnPropertyChanged(this,null); } And views communicate user actions like button clicks, tree view item selections, etc using commands. When user clicks on ‘Start the Meter’ button it invokes the method StartMeterCommand, which calls the method OnStartMeter which publishes the event to TotalViewModel using event aggregator  and TaxiStartedEvent. namespace TaxiModules.ViewModels { public class TotalViewModel:ObservableBase { ... private IEventAggregator _eventAggregator;   public TotalViewModel(IEventAggregator eventAggregator) { _eventAggregator = eventAggregator;   InitializePropertyNames(); InitializeModel(); SubscribeToEvents(); }   public decimal? TotalFare { get { return _totalFare; } set { _totalFare = value; RaisePropertyChanged(_totalFarePropertyName); } } .... private void SubscribeToEvents() { _eventAggregator.GetEvent<TaxiStartedEvent>().Subscribe(OnTaxiStarted, ThreadOption.UIThread,false,(filter) => true); _eventAggregator.GetEvent<TaxiOnMoveEvent>().Subscribe(OnTaxiMove, ThreadOption.UIThread, false, (filter) => true); _eventAggregator.GetEvent<TaxiResetEvent>().Subscribe(OnTaxiReset, ThreadOption.UIThread, false, (filter) => true); }   private void OnTaxiStarted(TaxiStarted taxiStarted) { Fares.Add(new EntryFare()); Fares.Add(new StateTaxFare(taxiStarted)); Fares.Add(new NightSurchargeFare(taxiStarted)); Fares.Add(new PeakHourWeekdayFare(taxiStarted));   SetTotalFare(Fares); }   private void SetTotalFare(IEnumerable<IFare> fares) { TotalFare = (_totalFare ?? 0) + TaxiFareHelper.GetTotalFare(fares); } ....   } }   TotalViewModel subscribes to events, TaxiStartedEvent and rest. When TaxiStartedEvent gets invoked it calls the OnTaxiStarted method which sets the total fare which includes entry fee, state tax, nightly surcharge, peak hour weekday fare.   Note that TotalViewModel derives from ObservableBase which implements the method RaisePropertyChanged which we are invoking in Set of TotalFare property, i.e, once we update the TotalFare property it raises an the event that  allows the TotalFare text box to fetch the new value through the data context. ViewModel is communicating with View through data context and it has no knowledge about View, helping in loose coupling of ViewModel and View.   I have attached the source code (.Net 4.0, Prism 4.0, VS 2010) , download and play with it and don’t forget to leave your comments.  

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  • Oracle Support Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1)

    - by faye.todd(at)oracle.com
    Master Note for Troubleshooting Advanced Queuing and Oracle Streams Propagation Issues (Doc ID 233099.1) Copyright (c) 2010, Oracle Corporation. All Rights Reserved. In this Document  Purpose  Last Review Date  Instructions for the Reader  Troubleshooting Details     1. Scope and Application      2. Definitions and Classifications     3. How to Use This Guide     4. Basic AQ Propagation Troubleshooting     5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages     6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment     7. Performance Issues  References Applies to: Oracle Server - Enterprise Edition - Version: 8.1.7.0 to 11.2.0.2 - Release: 8.1.7 to 11.2Information in this document applies to any platform. Purpose This document presents a step-by-step methodology for troubleshooting and resolving problems with Advanced Queuing Propagation in both Streams and basic Advanced Queuing environments. It also serves as a master reference for other more specific notes on Oracle Streams Propagation and Advanced Queuing Propagation issues. Last Review Date December 20, 2010 Instructions for the Reader A Troubleshooting Guide is provided to assist in debugging a specific issue. When possible, diagnostic tools are included in the document to assist in troubleshooting. Troubleshooting Details 1. Scope and Application This note is intended for Database Administrators of Oracle databases where issues are being encountered with propagating messages between advanced queues, whether the queues are used for user-created messaging systems or for Oracle Streams. It contains troubleshooting steps and links to notes for further problem resolution.It can also be used a template to document a problem when it is necessary to engage Oracle Support Services. Knowing what is NOT happening can frequently speed up the resolution process by focusing solely on the pertinent problem area. This guide is divided into five parts: Section 2: Definitions and Classifications (discusses the different types and features of propagations possible - helpful for understanding the rest of the guide) Section 3: How to Use this Guide (to be used as a start part for determining the scope of the problem and what sections to consult) Section 4. Basic AQ propagation troubleshooting (applies to both AQ propagation of user enqueued and dequeued messages as well as Oracle Streams propagations) Section 5. Additional troubleshooting steps for AQ propagation of user enqueued and dequeued messages Section 6. Additional troubleshooting steps for Oracle Streams propagation Section 7. Performance issues 2. Definitions and Classifications Given the potential scope of issues that can be encountered with AQ propagation, the first recommended step is to do some basic diagnosis to determine the type of problem that is being encountered. 2.1. What Type of Propagation is Being Used? 2.1.1. Buffered Messaging For an advanced queue, messages can be maintained on disk (persistent messaging) or in memory (buffered messaging). To determine if a queue is buffered or not, reference the GV_$BUFFERED_QUEUES view. If the queue does not appear in this view, it is persistent. 2.1.2. Propagation mode - queue-to-dblink vs queue-to-queue As of 10.2, an AQ propagation can also be defined as queue-to-dblink, or queue-to-queue: queue-to-dblink: The propagation delivers messages or events from the source queue to all subscribing queues at the destination database identified by the dblink. A single propagation schedule is used to propagate messages to all subscribing queues. Hence any changes made to this schedule will affect message delivery to all the subscribing queues. This mode does not support multiple propagations from the same source queue to the same target database. queue-to-queue: Added in 10.2, this propagation mode delivers messages or events from the source queue to a specific destination queue identified on the database link. This allows the user to have fine-grained control on the propagation schedule for message delivery. This new propagation mode also supports transparent failover when propagating to a destination Oracle RAC system. With queue-to-queue propagation, you are no longer required to re-point a database link if the owner instance of the queue fails on Oracle RAC. This mode supports multiple propagations to the same target database if the target queues are different. The default is queue-to-dblink. To verify if queue-to-queue propagation is being used, in non-Streams environments query DBA_QUEUE_SCHEDULES.DESTINATION - if a remote queue is listed along with the remote database link, then queue-to-queue propagation is being used. For Streams environments, the DBA_PROPAGATION.QUEUE_TO_QUEUE column can be checked.See the following note for a method to switch between the two modes:Document 827473.1 How to alter propagation from queue-to-queue to queue-to-dblink 2.1.3. Combined Capture and Apply (CCA) for Streams In 11g Oracle Streams environments, an optimization called Combined Capture and Apply (CCA) is implemented by default when possible. Although a propagation is configured in this case, Streams does not use it; instead it passes information directly from capture to an apply receiver. To see if CCA is in use: COLUMN CAPTURE_NAME HEADING 'Capture Name' FORMAT A30COLUMN OPTIMIZATION HEADING 'CCA Mode?' FORMAT A10SELECT CAPTURE_NAME, DECODE(OPTIMIZATION,0, 'No','Yes') OPTIMIZATIONFROM V$STREAMS_CAPTURE; Also, see the following note:Document 463820.1 Streams Combined Capture and Apply in 11g 2.2. Queue Table Compatibility There are three types of queue table compatibility. In more recent databases, queue tables may be present in all three modes of compatibility: 8.0 - earliest version, deprecated in 10.2 onwards 8.1 - support added for RAC, asynchronous notification, secure queues, queue level access control, rule-based subscribers, separate storage of history information 10.0 - if the database is in 10.1-compatible mode, then the default value for queue table compatibility is 10.0 2.3. Single vs Multiple Consumer Queue Tables If more than one recipient can dequeue a message from a queue, then its queue table is multiple consumer. You can propagate messages from a multiple-consumer queue to a single-consumer queue. Propagation from a single-consumer queue to a multiple-consumer queue is not possible. 3. How to Use This Guide 3.1. Are Messages Being Propagated at All, or is the Propagation Just Slow? Run the following query on the source database for the propagation (assuming that it is running): select TOTAL_NUMBER from DBA_QUEUE_SCHEDULES where QNAME='<source_queue_name>'; If TOTAL_NUMBER is increasing, then propagation is most likely functioning, although it may be slow. For performance issues, see Section 7. 3.2. Propagation Between Persistent User-Created Queues See Sections 4 and 5 (and optionally Section 6 if performance is an issue). 3.3. Propagation Between Buffered User-Created Queues See Sections 4, 5, and 6 (and optionally Section 7 if performance is an issue). 3.4. Propagation between Oracle Streams Queues (without Combined Capture and Apply (CCA) Optimization) See Sections 4 and 6 (and optionally Section 7 if performance is an issue). 3.5. Propagation between Oracle Streams Queues (with Combined Capture and Apply (CCA) Optimization) Although an AQ propagation is not used directly in this case, some characteristics of the message transfer are inferred from the propagation parameters used. Some parts of Sections 4 and 6 still apply. 3.6. Messaging Gateway Propagations This note does not apply to Messaging Gateway propagations. 4. Basic AQ Propagation Troubleshooting 4.1. Double-check Your Code Make sure that you are consistent in your usage of the database link(s) names, queue names, etc. It may be useful to plot a diagram of which queues are connected via which database links to make sure that the logical structure is correct. 4.2. Verify that Job Queue Processes are Running 4.2.1. Versions 10.2 and Lower - DBA_JOBS Package For versions 10.2 and lower, a scheduled propagation is managed by DBMS_JOB package. The propagation is performed by job queue process background processes. Therefore we need to verify that there are sufficient processes available for the propagation process. We should have at least 4 job queue processes running and preferably more depending on the number of other jobs running in the database. It should be noted that for AQ specific work, AQ will only ever use half of the job queue processes available.An issue caused by an inadequate job queue processes parameter setting is described in the following note:Document 298015.1 Kwqjswproc:Excep After Loop: Assigning To Self 4.2.1.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; 4.2.1.2. Job Queue Processes in Memory The following command will show how many job queue processes are currentlyin use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.1.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (spids) of job queue processes involved in propagation via select p.SPID, p.PROGRAM from V$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOBand j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%'; and these SPIDs can be used to check at the operating system level that they exist.In 8i a job queue process will have a name similar to: ora_snp1_<instance_name>.In 9i onwards you will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.2.2. Version 11.1 and Above - Oracle Scheduler In version 11.1 and above, Oracle Scheduler is used to perform AQ and Streams propagations. Oracle Scheduler automatically tunes the number of slave processes for these jobs based on the load on the computer system, and the JOB_QUEUE_PROCESSES initialization parameter is only used to specify the maximum number of slave processes. Therefore, the JOB_QUEUE_PROCESSES initialization parameter does not need to be set (it defaults to a very high number), unless you want to limit the number of slaves that can be created. If JOB_QUEUE_PROCESSES = 0, no propagation jobs will run.See the following note for a discussion of Oracle Streams 11g and Oracle Scheduler:Document 1083608.1 11g Streams and Oracle Scheduler 4.2.2.1. Job Queue Processes in Initalization Parameter File The parameter JOB_QUEUE_PROCESSES in the init.ora/spfile should be > 0, and preferably be left at its default value. The value can be changed dynamically via connect / as sysdbaalter system set JOB_QUEUE_PROCESSES=10; To set the JOB_QUEUE_PROCESSES parameter to its default value, run: connect / as sysdbaalter system reset JOB_QUEUE_PROCESSES; and then bounce the instance. 4.2.2.2. Job Queue Processes in Memory The following command will show how many job queue processes are currently in use by this instance (this may be different than what is in the init.ora/spfile): connect / as sysdbashow parameter job; 4.2.2.3. OS PIDs Corresponding to Job Queue Processes Identify the operating system process ids (SPIDs) of job queue processes involved in propagation via col PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_namefrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDRand jr.JOB_name=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%'; and these SPIDs can be used to check at the operating system level that they exist.You will see a coordinator process: ora_cjq0_ and multiple slave processes: ora_jnnn_<instance_name>, where nnn is an integer between 1 and 999. 4.3. Check the Alert Log and Any Associated Trace Files The first place to check for propagation failures is the alert logs at all sites (local and if relevant all remote sites). When a job queue process attempts to execute a schedule and fails it will always write an error stack to the alert log. This error stack will also be written in a job queue process trace file, which will be written to the BACKGROUND_DUMP_DEST location for 10.2 and below, and in the DIAGNOSTIC_DEST location for 11g. The fact that errors are written to the alert log demonstrates that the schedule is executing. This means that the problem could be with the set up of the schedule. In this example the ORA-02068 demonstrates that the failure was at the remote site. Further investigation revealed that the remote database was not open, hence the ORA-03114 error. Starting the database resolved the problem. Thu Feb 14 10:40:05 2002 Propagation Schedule for (AQADM.MULTIPLEQ, SHANE816.WORLD) encountered following error:ORA-04052: error occurred when looking up Remote object [email protected]: error occurred at recursive SQL level 4ORA-02068: following severe error from SHANE816ORA-03114: not connected to ORACLEORA-06512: at "SYS.DBMS_AQADM_SYS", line 4770ORA-06512: at "SYS.DBMS_AQADM", line 548ORA-06512: at line 1 Other potential errors that may be written to the alert log can be found in the following notes:Document 827184.1 AQ Propagation with CLOB data types Fails with ORA-22990 (11.1)Document 846297.1 AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn] (10.2, 11.1)Document 731292.1 ORA-25215 Reported on Local Propagation When Using Transformation with ANYDATA queue tables (10.2, 11.1, 11.2)Document 365093.1 ORA-07445 [kwqppay2aqe()+7360] Reported on Propagation of a Transformed Message (10.1, 10.2)Document 219416.1 Advanced Queuing Propagation Fails with ORA-22922 (9.0)Document 1203544.1 AQ Propagation Aborted with ORA-600 [ociksin: invalid status] on SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE After Upgrade (11.1, 11.2)Document 1087324.1 ORA-01405 ORA-01422 reported by Advanced Queuing Propagation schedules after RAC reconfiguration (10.2)Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370 incorrect usage of method" (9.2, 10.2, 11.1, 11.2)Document 332792.1 ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up Statspack (8.1, 9.0, 9.2, 10.1)Document 353325.1 ORA-24056: Internal inconsistency for QUEUE <queue_name> and destination <dblink> (8.1, 9.0, 9.2, 10.1, 10.2, 11.1, 11.2)Document 787367.1 ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2 (10.1, 10.2)Document 566622.1 ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1 (9.2, 10.1)Document 731539.1 ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTP (9.0, 9.2, 10.1, 10.2, 11.1)Document 253131.1 Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555) (9.2)Document 118884.1 How to unschedule a propagation schedule stuck in pending stateDocument 222992.1 DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 1204080.1 AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.Document 1233675.1 AQ Propagation stops after upgrade to 11.2.0.1 ORA-30757 4.3.1. Errors Related to Incorrect Network Configuration The most common propagation errors result from an incorrect network configuration. The list below contains common errors caused by tnsnames.ora file or database links being configured incorrectly: - ORA-12154: TNS:could not resolve service name- ORA-12505: TNS:listener does not currently know of SID given in connect descriptor- ORA-12514: TNS:listener could not resolve SERVICE_NAME - ORA-12541: TNS-12541 TNS:no listener 4.4. Check the Database Links Exist and are Functioning Correctly For schedules to remote databases confirm the database link exists via. SQL> col DBLINK for a45SQL> select QNAME, NVL(REGEXP_SUBSTR(DESTINATION, '[^@]+', 1, 2), DESTINATION) dblink2 from DBA_QUEUE_SCHEDULES3 where MESSAGE_DELIVERY_MODE = 'PERSISTENT';QNAME DBLINK------------------------------ ---------------------------------------------MY_QUEUE ORCL102B.WORLD Connect as the owner of the link and select across it to verify it works and connects to the database we expect. i.e. select * from ALL_QUEUES@ ORCL102B.WORLD; You need to ensure that the userid that scheduled the propagation (using DBMS_AQADM.SCHEDULE_PROPAGATION or DBMS_PROPAGATION_ADM.CREATE_PROPAGATION if using Streams) has access to the database link for the destination. 4.5. Has Propagation Been Correctly Scheduled? Check that the propagation schedule has been created and that a job queue process has been assigned. Look for the entry in DBA_QUEUE_SCHEDULES and SYS.AQ$_SCHEDULES for your schedule. For 10g and below, check that it has a JOBNO entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_JOBS with that JOBNO. For 11g and above, check that the schedule has a JOB_NAME entry in SYS.AQ$_SCHEDULES, and that there is an entry in DBA_SCHEDULER_JOBS with that JOB_NAME. Check the destination is as intended and spelled correctly. SQL> select SCHEMA, QNAME, DESTINATION, SCHEDULE_DISABLED, PROCESS_NAME from DBA_QUEUE_SCHEDULES;SCHEMA QNAME DESTINATION S PROCESS------- ---------- ------------------ - -----------AQADM MULTIPLEQ AQ$_LOCAL N J000 AQ$_LOCAL in the destination column shows that the queue to which we are propagating to is in the same database as the source queue. If the propagation was to a remote (different) database, a database link will be in the DESTINATION column. The entry in the SCHEDULE_DISABLED column, N, means that the schedule is NOT disabled. If Y (yes) appears in this column, propagation is disabled and the schedule will not be executed. If not using Oracle Streams, propagation should resume once you have enabled the schedule by invoking DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE (for 10.2 Oracle Streams and above, the DBMS_PROPAGATION_ADM.START_PROPAGATION procedure should be used). The PROCESS_NAME is the name of the job queue process currently allocated to execute the schedule. This process is allocated dynamically at execution time. If the PROCESS_NAME column is null (empty) the schedule is not currently executing. You may need to execute this statement a number of times to verify if a process is being allocated. If a process is at some time allocated to the schedule, it is attempting to execute. SQL> select SCHEMA, QNAME, LAST_RUN_DATE, NEXT_RUN_DATE from DBA_QUEUE_SCHEDULES;SCHEMA QNAME LAST_RUN_DATE NEXT_RUN_DATE------ ----- ----------------------- ----------------------- AQADM MULTIPLEQ 13-FEB-2002 13:18:57 13-FEB-2002 13:20:30 In 11g, these dates are expressed in TIMESTAMP WITH TIME ZONE datatypes. If the NEXT_RUN_DATE and NEXT_RUN_TIME columns are null when this statement is executed, the scheduled propagation is currently in progress. If they never change it would suggest that the schedule itself is never executing. If the next scheduled execution is too far away, change the NEXT_TIME parameter of the schedule so that schedules are executed more frequently (assuming that the window is not set to be infinite). Parameters of a schedule can be changed using the DBMS_AQADM.ALTER_PROPAGATION_SCHEDULE call. In 10g and below, scheduling propagation posts a job in the DBA_JOBS view. The columns are more or less the same as DBA_QUEUE_SCHEDULES so you just need to recognize the job and verify that it exists. SQL> select JOB, WHAT from DBA_JOBS where WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';JOB WHAT---- ----------------- 720 next_date := sys.dbms_aqadm.aq$_propaq(job); For 11g, scheduling propagation posts a job in DBA_SCHEDULER_JOBS instead: SQL> select JOB_NAME from DBA_SCHEDULER_JOBS where JOB_NAME like 'AQ_JOB$_%';JOB_NAME------------------------------AQ_JOB$_41 If no job exists, check DBA_QUEUE_SCHEDULES to make sure that the schedule has not been disabled. For 10g and below, the job number is dynamic for AQ propagation schedules. The procedure that is executed to expedite a propagation schedule runs, removes itself from DBA_JOBS, and then reposts a new job for the next scheduled propagation. The job number should therefore always increment unless the schedule has been set up to run indefinitely. 4.6. Is the Schedule Executing but Failing to Complete? Run the following query: SQL> select FAILURES, LAST_ERROR_MSG from DBA_QUEUE_SCHEDULES;FAILURES LAST_ERROR_MSG------------ -----------------------1 ORA-25207: enqueue failed, queue AQADM.INQ is disabled from enqueueingORA-02063: preceding line from SHANE816 The failures column shows how many times we have attempted to execute the schedule and failed. Oracle will attempt to execute the schedule 16 times after which it will be removed from the DBA_JOBS or DBA_SCHEDULER_JOBS view and the schedule will become disabled. The column DBA_QUEUE_SCHEDULES.SCHEDULE_DISABLED will show 'Y'. For 11g and above, the DBA_SCHEDULER_JOBS.STATE column will show 'BROKEN' for the job corresponding to DBA_QUEUE_SCHEDULES.JOB_NAME. Prior to 10g the back off algorithm for failures was exponential, whereas from 10g onwards it is linear. The propagation will become disabled on the 17th attempt. Only the last execution failure will be reflected in the LAST_ERROR_MSG column. That is, if the schedule fails 5 times for 5 different reasons, only the last set of errors will be recorded in DBA_QUEUE_SCHEDULES. Any errors need to be resolved to allow propagation to continue. If propagation has also become disabled due to 17 failures, first resolve the reason for the error and then re-enable the schedule using the DBMS_AQADM.ENABLE_PROPAGATION_SCHEDULE procedure, or DBMS_PROPAGATION_ADM.START_PROPAGATION if using 10.2 or above Oracle Streams. As soon as the schedule executes successfully the error message entries will be deleted. Oracle does not keep a history of past failures. However, when using Oracle Streams, the errors will be retained in the DBA_PROPAGATION view even after the schedule resumes successfully. See the following note for instructions on how to clear out the errors from the DBA_PROPAGATION view:Document 808136.1 How to clear the old errors from DBA_PROPAGATION view?If a schedule is active and no errors are being reported then the source queue may not have any messages to be propagated. 4.7. Do the Propagation Notification Queue Table and Queue Exist? Check to see that the propagation notification queue table and queue exist and are enabled for enqueue and dequeue. Propagation makes use of the propagation notification queue for handling propagation run-time events, and the messages in this queue are stored in a SYS-owned queue table. This queue should never be stopped or dropped and the corresponding queue table never be dropped. 10g and belowThe propagation notification queue table is of the format SYS.AQ$_PROP_TABLE_n, where 'n' is the RAC instance number, i.e. '1' for a non-RAC environment. This queue and queue table are created implicitly when propagation is first scheduled. If propagation has been scheduled and these objects do not exist, try unscheduling and rescheduling propagation. If they still do not exist contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ$_PROP_TABLE_1SQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ$_PROP_NOTIFY_1 YES YESAQ$_AQ$_PROP_TABLE_1_E NO NO If the AQ$_PROP_NOTIFY_1 queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_1_E should not be enabled for enqueue or dequeue.11g and aboveThe propagation notification queue table is of the format SYS.AQ_PROP_TABLE, and is created when the database is created. If they do not exist, contact Oracle Support. SQL> select QUEUE_TABLE from DBA_QUEUE_TABLES2 where QUEUE_TABLE like '%PROP_TABLE%' and OWNER = 'SYS';QUEUE_TABLE------------------------------AQ_PROP_TABLESQL> select NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED2 from DBA_QUEUES where owner='SYS'3 and QUEUE_TABLE like '%PROP_TABLE%';NAME ENQUEUE DEQUEUE------------------------------ ------- -------AQ_PROP_NOTIFY YES YESAQ$_AQ_PROP_TABLE_E NO NO If the AQ_PROP_NOTIFY queue is not enabled for enqueue or dequeue, it should be so enabled using DBMS_AQADM.START_QUEUE. However, the exception queue AQ$_AQ$_PROP_TABLE_E should not be enabled for enqueue or dequeue. 4.8. Does the Remote Queue Exist and is it Enabled for Enqueueing? Check that the remote queue the propagation is transferring messages to exists and is enabled for enqueue: SQL> select DESTINATION from USER_QUEUE_SCHEDULES where QNAME = 'OUTQ';DESTINATION-----------------------------------------------------------------------------"AQADM"."INQ"@M2V102.ESSQL> select OWNER, NAME, ENQUEUE_ENABLED, DEQUEUE_ENABLED from [email protected];OWNER NAME ENQUEUE DEQUEUE-------- ------ ----------- -----------AQADM INQ YES YES 4.9. Do the Target and Source Database Charactersets Differ? If a message fails to propagate, check the database charactersets of the source and target databases. Investigate whether the same message can propagate between the databases with the same characterset or it is only a particular combination of charactersets which causes a problem. 4.10. Check the Queue Table Type Agreement Propagation is not possible between queue tables which have types that differ in some respect. One way to determine if this is the case is to run the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure for the two queues that the propagation operates on. If the types do not agree, DBMS_AQADM.VERIFY_QUEUE_TYPES will return '0'.For AQ propagation between databases which have different NLS_LENGTH_SEMANTICS settings, propagation will not work, unless the queues are Oracle Streams ANYDATA queues.See the following notes for issues caused by lack of type agreement:Document 1079577.1 Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"Document 282987.1 Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueDocument 353754.1 Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT 4.11. Enable Propagation Tracing 4.11.1. System Level This is set it in the init.ora/spfile as follows: event="24040 trace name context forever, level 10" and restart the instanceThis event cannot be set dynamically with an alter system command until version 10.2: SQL> alter system set events '24040 trace name context forever, level 10'; To unset the event: SQL> alter system set events '24040 trace name context off'; Debugging information will be logged to job queue trace file(s) (jnnn) as propagation takes place. You can check the trace file for errors, and for statements indicating that messages have been sent. For the most part the trace information is understandable. This trace should also be uploaded to Oracle Support if a service request is created. 4.11.2. Attaching to a Specific Process We can also attach to an existing job queue processes that is running a propagation schedule and trace it individually using the oradebug utility, as follows:10.2 and below connect / as sysdbaselect p.SPID, p.PROGRAM from v$PROCESS p, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j where s.SID=jr.SID and s.PADDR=p.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 11g connect / as sysdbacol PROGRAM for a30select p.SPID, p.PROGRAM, j.JOB_NAMEfrom v$PROCESS p, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j where s.SID=jr.SESSION_ID and s.PADDR=p.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%';-- For the process id (SPID) attach to it via oradebug and generate the following traceoradebug setospid <SPID>oradebug unlimitoradebug Event 10046 trace name context forever, level 12oradebug Event 24040 trace name context forever, level 10-- Trace the process for 5 minutesoradebug Event 10046 trace name context offoradebug Event 24040 trace name context off-- The following command returns the pathname/filename to the file being written tooradebug tracefile_name 4.11.3. Further Tracing The previous tracing steps only trace the job queue process executing the propagation on the source. At times it is useful to trace the propagation receiver process (the session which is enqueueing the messages into the target queue) on the target database which is associated with the job queue process on the source database.These following queries provide ways of identifying the processes involved in propagation so that you can attach to them via oradebug to generate trace information.In order to identify the propagation receiver process you need to execute the query as a user with privileges to access the v$ views in both the local and remote databases so the database link must connect as a user with those privileges in the remote database. The <DBLINK> in the queries should be replaced by the appropriate database link.The queries have two forms due to the differences between operating systems. The value returned by 'Rem Process' is the operating system identifier of the propagation receiver on the remote database. Once identified, this process can be attached to and traced on the remote database using the commands given in Section 4.11.2.10.2 and below - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from v$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 10.2 and below - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_JOBS_RUNNING jr, V$SESSION s, DBA_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SID and s.PADDR=pl.ADDR and jr.JOB=j.JOB and j.WHAT like '%sys.dbms_aqadm.aq$_propaq(job)%' and pl.SPID=sr.PROCESS; 11g - Windows select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=substr(sr.PROCESS, instr(sr.PROCESS,':')+1); 11g - Unix select pl.SPID "JobQ Process", pl.PROGRAM, sr.PROCESS "Rem Process" from V$PROCESS pl, DBA_SCHEDULER_RUNNING_JOBS jr, V$SESSION s, DBA_SCHEDULER_JOBS j, V$SESSION@<DBLINK> sr where s.SID=jr.SESSION_ID and s.PADDR=pl.ADDR and jr.JOB_NAME=j.JOB_NAME and j.JOB_NAME like '%AQ_JOB$_%%' and pl.SPID=sr.PROCESS;   5. Additional Troubleshooting Steps for AQ Propagation of User-Enqueued and Dequeued Messages 5.1. Check the Privileges of All Users Involved Ensure that the owner of the database link has the necessary privileges on the aq packages. SQL> select TABLE_NAME, PRIVILEGE from USER_TAB_PRIVS;TABLE_NAME PRIVILEGE------------------------------ ----------------------------------------DBMS_LOCK EXECUTEDBMS_AQ EXECUTEDBMS_AQADM EXECUTEDBMS_AQ_BQVIEW EXECUTEQT52814_BUFFER SELECT Note that when queue table is created, a view called QT<nnn>_BUFFER is created in the SYS schema, and the queue table owner is given SELECT privileges on it. The <nnn> corresponds to the object_id of the associated queue table. SQL> select * from USER_ROLE_PRIVS;USERNAME GRANTED_ROLE ADM DEF OS_------------------------------ ------------------------------ ---- ---- ---AQ_USER1 AQ_ADMINISTRATOR_ROLE NO YES NOAQ_USER1 CONNECT NO YES NOAQ_USER1 RESOURCE NO YES NO It is good practice to configure central AQ administrative user. All admin and processing jobs are created, executed and administered as this user. This configuration is not mandatory however, and the database link can be owned by any existing queue user. If this latter configuration is used, ensure that the connecting user has the necessary privileges on the AQ packages and objects involved. Privileges for an AQ Administrative user Execute on DBMS_AQADM Execute on DBMS_AQ Granted the AQ_ADMINISTRATOR_ROLE Privileges for an AQ user Execute on DBMS_AQ Execute on the message payload Enqueue privileges on the remote queue Dequeue privileges on the originating queue Privileges need to be confirmed on both sites when propagation is scheduled to remote destinations. Verify that the user ID used to login to the destination through the database link has been granted privileges to use AQ. 5.2. Verify Queue Payload Types AQ will not propagate messages from one queue to another if the payload types of the two queues are not verified to be equivalent. An AQ administrator can verify if the source and destination's payload types match by executing the DBMS_AQADM.VERIFY_QUEUE_TYPES procedure. The results of the type checking will be stored in the SYS.AQ$_MESSAGE_TYPES table. This table can be accessed using the object identifier OID of the source queue and the address database link of the destination queue, i.e. [schema.]queue_name[@destination]. Prior to Oracle 9i the payload (message type) had to be the same for all the queue tables involved in propagation. From Oracle9i onwards a transformation can be used so that payloads can be converted from one type to another. The following procedural call made on the source database can verify whether we can propagate between the source and the destination queue tables. connect aq_user1/[email protected] serverout onDECLARErc_value number;BEGINDBMS_AQADM.VERIFY_QUEUE_TYPES(src_queue_name => 'AQ_USER1.Q_1', dest_queue_name => 'AQ_USER2.Q_2',destination => 'dbl_aq_user2.es',rc => rc_value);dbms_output.put_line('rc_value code is '||rc_value);END;/ If propagation is possible then the return code value will be 1. If it is 0 then propagation is not possible and further investigation of the types and transformations used by and in conjunction with the queue tables is required. With regard to comparison of the types the following sql can be used to extract the DDL for a specific type with' %' changed appropriately on the source and target. This can then be compared for the source and target. SET LONG 20000 set pagesize 50 EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'STORAGE',false); SELECT DBMS_METADATA.GET_DDL('TYPE',t.type_name) from user_types t WHERE t.type_name like '%'; EXECUTE DBMS_METADATA.SET_TRANSFORM_PARAM(DBMS_METADATA.SESSION_TRANSFORM, 'DEFAULT'); 5.3. Check Message State and Destination The first step in this process is to identify the queue table associated with the problem source queue. Although you schedule propagation for a specific queue, most of the meta-data associated with that queue is stored in the underlying queue table. The following statement finds the queue table for a given queue (note that this is a multiple-consumer queue table). SQL> select QUEUE_TABLE from DBA_QUEUES where NAME = 'MULTIPLEQ';QUEUE_TABLE --------------------MULTIPLEQTABLE For a small amount of messages in a multiple-consumer queue table, the following query can be run: SQL> select MSG_STATE, CONSUMER_NAME, ADDRESS from AQ$MULTIPLEQTABLE where QUEUE = 'MULTIPLEQ';MSG_STATE CONSUMER_NAME ADDRESS-------------- ----------------------- -------------READY AQUSER2 [email protected] AQUSER1READY AQUSER3 AQADM.INQ In this example we see 2 messages ready to be propagated to remote queues and 1 that is not. If the address column is blank, the message is not scheduled for propagation and can only be dequeued from the queue upon which it was enqueued. The MSG_STATE column values are discussed in Document 102330.1 Advanced Queueing MSG_STATE Values and their Interpretation. If the address column has a value, the message has been enqueued for propagation to another queue. The first row in the example includes a database link (@M2V102.ES). This demonstrates that the message should be propagated to a queue at a remote database. The third row does not include a database link so will be propagated to a queue that resides on the same database as the source queue. The consumer name is the intended recipient at the target queue. Note that we are not querying the base queue table directly; rather, we are querying a view that is available on top of every queue table, AQ$<queue_table_name>.A more realistic query in an environment where the queue table contains thousands of messages is8.0.3-compatible multiple-consumer queue table and all compatibility single-consumer queue tables select count(*), MSG_STATE, QUEUE from AQ$<queue_table_name>  group by MSG_STATE, QUEUE; 8.1.3 and 10.0-compatible queue tables select count(*), MSG_STATE, QUEUE, CONSUMER_NAME from AQ$<queue_table_name>group by MSG_STATE, QUEUE, CONSUMER_NAME; For multiple-consumer queue tables, if you did not see the expected CONSUMER_NAME , check the syntax of the enqueue code and verify the recipients are declared correctly. If a recipients list is not used on enqueue, check the subscriber list in the AQ$_<queue_table_name>_S view (note that a single-consumer queue table does not have a subscriber view. This view records all members of the default subscription list which were added using the DBMS_AQADM.ADD_SUBSCRIBER procedure and also those enqueued using a recipient list. SQL> select QUEUE, NAME, ADDRESS from AQ$MULTIPLEQTABLE_S;QUEUE NAME ADDRESS---------- ----------- -------------MULTIPLEQ AQUSER2 [email protected] AQUSER1 In this example we have 2 subscribers registered with the queue. We have a local subscriber AQUSER1, and a remote subscriber AQUSER2, on the queue INQ, owned by AQADM, at M2V102.ES. Unless overridden with a recipient list during enqueue every message enqueued to this queue will be propagated to INQ at M2V102.ES.For 8.1 style and above multiple consumer queue tables, you can also check the following information at the target: select CONSUMER_NAME, DEQ_TXN_ID, DEQ_TIME, DEQ_USER_ID, PROPAGATED_MSGID from AQ$<queue_table_name> where QUEUE = '<QUEUE_NAME>'; For 8.0 style queues, if the queue table supports multiple consumers you can obtain the same information from the history column of the queue table: select h.CONSUMER, h.TRANSACTION_ID, h.DEQ_TIME, h.DEQ_USER, h.PROPAGATED_MSGIDfrom AQ$<queue_table_name> t, table(t.history) h where t.Q_NAME = '<QUEUE_NAME>'; A non-NULL TRANSACTION_ID indicates that the message was successfully propagated. Further, the DEQ_TIME indicates the time of propagation, the DEQ_USER indicates the userid used for propagation, and the PROPAGATED_MSGID indicates the message ID of the message that was enqueued at the destination. 6. Additional Troubleshooting Steps for Propagation in an Oracle Streams Environment 6.1. Is the Propagation Enabled? For a propagation job to propagate messages, the propagation must be enabled. For Streams, a special view called DBA_PROPAGATION exists to convey information about Streams propagations. If messages are not being propagated by a propagation as expected, then the propagation might not be enabled. To query for this: SELECT p.PROPAGATION_NAME, DECODE(s.SCHEDULE_DISABLED, 'Y', 'Disabled','N', 'Enabled') SCHEDULE_DISABLED, s.PROCESS_NAME, s.FAILURES, s.LAST_ERROR_MSGFROM DBA_QUEUE_SCHEDULES s, DBA_PROPAGATION pWHERE p.DESTINATION_DBLINK = NVL(REGEXP_SUBSTR(s.DESTINATION, '[^@]+', 1, 2), s.DESTINATION) AND s.SCHEMA = p.SOURCE_QUEUE_OWNER AND s.QNAME = p.SOURCE_QUEUE_NAME AND MESSAGE_DELIVERY_MODE = 'PERSISTENT' order by PROPAGATION_NAME; At times, the propagation job may become "broken" or fail to start after an error has been encountered or after a database restart. If an error is indicated by the above query, an attempt to disable the propagation and then re-enable it can be made. In the examples below, for the propagation named STRMADMIN_PROPAGATE where the queue name is STREAMS_QUEUE owned by STRMADMIN and the destination database link is ORCL2.WORLD, the commands would be:10.2 and above exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE'); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); If the above does not fix the problem, stop the propagation specifying the force parameter (2nd parameter on stop_propagation) as TRUE: exec dbms_propagation_adm.stop_propagation('STRMADMIN_PROPAGATE',true); exec dbms_propagation_adm.start_propagation('STRMADMIN_PROPAGATE'); The statistics for the propagation as well as any old error messages are cleared when the force parameter is set to TRUE. Therefore if the propagation schedule is stopped with FORCE set to TRUE, and upon restart there is still an error message in DBA_PROPAGATION, then the error message is current.9.2 or 10.1 exec dbms_aqadm.disable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms.aqadm.enable_propagation_schedule('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); If the above does not fix the problem, perform an unschedule of propagation and then schedule_propagation: exec dbms_aqadm.unschedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); exec dbms_aqadm.schedule_propagation('STRMADMIN.STREAMS_QUEUE','ORCL2.WORLD'); Typically if the error from the first query in Section 6.1 recurs after restarting the propagation as shown above, further troubleshooting of the error is needed. 6.2. Check Propagation Rule Sets and Transformations Inspect the configuration of the rules in the rule set that is associated with the propagation process to make sure that they evaluate to TRUE as expected. If not, then the object or schema will not be propagated. Remember that when a negative rule evaluates to TRUE, the specified object or schema will not be propagated. Finally inspect any rule-based transformations that are implemented with propagation to make sure they are changing the data in the intended way.The following query shows what rule sets are assigned to a propagation: select PROPAGATION_NAME, RULE_SET_OWNER||'.'||RULE_SET_NAME "Positive Rule Set",NEGATIVE_RULE_SET_OWNER||'.'||NEGATIVE_RULE_SET_NAME "Negative Rule Set"from DBA_PROPAGATION; The next two queries list the propagation rules and their conditions. The first is for the positive rule set, the second is for the negative rule set: set long 4000select rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES rwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER and RULE_SET_NAME in(select RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME;   set long 4000select c.PROPAGATION_NAME, rsr.RULE_SET_OWNER||'.'||rsr.RULE_SET_NAME RULE_SET ,rsr.RULE_OWNER||'.'||rsr.RULE_NAME RULE_NAME,r.RULE_CONDITION CONDITION fromDBA_RULE_SET_RULES rsr, DBA_RULES r ,DBA_PROPAGATION cwhere rsr.RULE_NAME = r.RULE_NAME and rsr.RULE_OWNER = r.RULE_OWNER andrsr.RULE_SET_OWNER=c.NEGATIVE_RULE_SET_OWNER and rsr.RULE_SET_NAME=c.NEGATIVE_RULE_SET_NAMEand rsr.RULE_SET_NAME in(select NEGATIVE_RULE_SET_NAME from DBA_PROPAGATION) order by rsr.RULE_SET_OWNER, rsr.RULE_SET_NAME; 6.3. Determining the Total Number of Messages and Bytes Propagated As in Section 3.1, determining if messages are flowing can be instructive to see whether the propagation is entirely hung or just slow. If the propagation is not in flow control (see Section 6.5.2), but the statistics are incrementing slowly, there may be a performance issue. For Streams implementations two views are available that can assist with this that can show the number of messages sent by a propagation, as well as the number of acknowledgements being returned from the target site: the V$PROPAGATION_SENDER view at the Source site and the V$PROPAGATION_RECEIVER view at the destination site. It is helpful to query both to determine if messages are being delivered to the target. Look for the statistics to increase.Source: select QUEUE_SCHEMA, QUEUE_NAME, DBLINK,HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS, TOTAL_BYTESfrom V$PROPAGATION_SENDER; Target: select SRC_QUEUE_SCHEMA, SRC_QUEUE_NAME, SRC_DBNAME, DST_QUEUE_SCHEMA, DST_QUEUE_NAME, HIGH_WATER_MARK, ACKNOWLEDGEMENT, TOTAL_MSGS from V$PROPAGATION_RECEIVER; 6.4. Check Buffered Subscribers The V$BUFFERED_SUBSCRIBERS view displays information about subscribers for all buffered queues in the instance. This view can be queried to make sure that the site that the propagation is propagating to is listed as a subscriber address for the site being propagated from: select QUEUE_SCHEMA, QUEUE_NAME, SUBSCRIBER_ADDRESS from V$BUFFERED_SUBSCRIBERS; The SUBSCRIBER_ADDRESS column will not be populated when the propagation is local (between queues on the same database). 6.5. Common Streams Propagation Errors 6.5.1. ORA-02082: A loopback database link must have a connection qualifier. This error can occur if you use the Streams Setup Wizard in Oracle Enterprise Manager without first configuring the GLOBAL_NAME for your database. 6.5.2. ORA-25307: Enqueue rate too high. Enable flow control DBA_QUEUE_SCHEDULES will display this informational message for propagation when the automatic flow control (10g feature of Streams) has been invoked.Similar to Streams capture processes, a Streams propagation process can also go into a state of 'flow control. This is an informative message that indicates flow control has been automatically enabled to reduce the rate at which messages are being enqueued into at target queue.This typically occurs when the target site is unable to keep up with the rate of messages flowing from the source site. Other than checking that the apply process is running normally on the target site, usually no action is required by the DBA. Propagation and the capture process will be resumed automatically when the target site is able to accept more messages.The following document contains more information:Document 302109.1 Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlSee the following document for one potential cause of this situation:Document 1097115.1 Oracle Streams Apply Reader is in 'Paused' State 6.5.3. ORA-25315 unsupported configuration for propagation of buffered messages This error typically occurs when the target database is RAC and usually indicates that an attempt was made to propagate buffered messages with the database link pointing to an instance in the destination database which is not the owner instance of the destination queue. To resolve the problem, use queue-to-queue propagation for buffered messages. 6.5.4. ORA-600 [KWQBMCRCPTS101] after dropping / recreating propagation For cause/fixes refer to:Document 421237.1 ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams Propagation 6.5.5. Stopping or Dropping a Streams Propagation Hangs See the following note:Document 1159787.1 Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It Hang 6.6. Streams Propagation-Related Notes for Common Issues Document 437838.1 Streams Specific PatchesDocument 749181.1 How to Recover Streams After Dropping PropagationDocument 368912.1 Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentDocument 564649.1 ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveDocument 553017.1 Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201Document 944846.1 Streams Propagation Fails Ora-7445 [kohrsmc]Document 745601.1 ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'Document 333068.1 ORA-23603: Streams Enqueue Aborted Eue To Low SGADocument 363496.1 Ora-25315 Propagating on RAC StreamsDocument 368237.1 Unable to Unschedule Propagation. Streams Queue is InvalidDocument 436332.1 dbms_propagation_adm.stop_propagation hangsDocument 727389.1 Propagation Fails With ORA-12528Document 730911.1 ORA-4063 Is Reported After Dropping Negative Prop.RulesetDocument 460471.1 Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsDocument 1165583.1 ORA-600 [kwqpuspse0-ack] In Streams EnvironmentDocument 1059029.1 Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationDocument 556309.1 Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedDocument 839568.1 Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''Document 311021.1 Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredDocument 359971.1 STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068Document 1101616.1 DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747 7. Performance Issues A propagation may seem to be slow if the queries from Sections 3.1 and 6.3 show that the message statistics are not changing quickly. In Oracle Streams, this more usually is due to a slow apply process at the target rather than a slow propagation. Propagation could be inferred to be slow if the message statistics are changing, and the state of a capture process according to V$STREAMS_CAPTURE.STATE is PAUSED FOR FLOW CONTROL, but an ORA-25307 'Enqueue rate too high. Enable flow control' warning is NOT observed in DBA_QUEUE_SCHEDULES per Section 6.5.2. If this is the case, see the following notes / white papers for suggestions to increase performance:Document 335516.1 Master Note for Streams Performance RecommendationsDocument 730036.1 Overview for Troubleshooting Streams Performance IssuesDocument 780733.1 Streams Propagation Tuning with Network ParametersWhite Paper: http://www.oracle.com/technetwork/database/features/availability/maa-wp-10gr2-streams-performance-130059.pdfWhite Paper: Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2, http://www.oracle.com/technetwork/database/features/availability/maa-10gr2-streams-configuration-132039.pdf, See APPENDIX A: USING STREAMS CONFIGURATIONS OVER A NETWORKFor basic AQ propagation, the network tuning in the aforementioned Appendix A of the white paper 'Oracle Streams Configuration Best Practices: Oracle Database 10g Release 10.2' is applicable. References NOTE:102330.1 - Advanced Queueing MSG_STATE Values and their InterpretationNOTE:102771.1 - Advanced Queueing Propagation using PL/SQLNOTE:1059029.1 - Combined Capture and Apply (CCA) : Capture aborts : ORA-1422 after schedule_propagationNOTE:1079577.1 - Advanced Queuing Propagation Fails With "ORA-22370: incorrect usage of method"NOTE:1083608.1 - 11g Streams and Oracle SchedulerNOTE:1087324.1 - ORA-01405 ORA-01422 reported by Adavanced Queueing Propagation schedules after RAC reconfigurationNOTE:1097115.1 - Oracle Streams Apply Reader is in 'Paused' StateNOTE:1101616.1 - DBMS_PROPAGATION_ADM.DROP_PROPAGATION FAILS WITH ORA-1747NOTE:1159787.1 - Troubleshooting Streams Propagation When It is Not Functioning and Attempts to Stop It HangNOTE:1165583.1 - ORA-600 [kwqpuspse0-ack] In Streams EnvironmentNOTE:118884.1 - How to unschedule a propagation schedule stuck in pending stateNOTE:1203544.1 - AQ PROPAGATION ABORTED WITH ORA-600[OCIKSIN: INVALID STATUS] ON SYS.DBMS_AQADM_SYS.AQ$_PROPAGATION_PROCEDURE AFTER UPGRADENOTE:1204080.1 - AQ Propagation Failing With ORA-25329 After Upgraded From 8i or 9i to 10g or 11g.NOTE:219416.1 - Advanced Queuing Propagation fails with ORA-22922NOTE:222992.1 - DBMS_AQADM.DISABLE_PROPAGATION_SCHEDULE Returns ORA-24082NOTE:253131.1 - Concurrent Writes May Corrupt LOB Segment When Using Auto Segment Space Management (ORA-1555)NOTE:282987.1 - Propagated Messages marked UNDELIVERABLE after Drop and Recreate Of Remote QueueNOTE:298015.1 - Kwqjswproc:Excep After Loop: Assigning To SelfNOTE:302109.1 - Streams Propagation Error: ORA-25307 Enqueue rate too high. Enable flow controlNOTE:311021.1 - Streams Propagation Process : Ora 12154 After Reboot with Transparent Application Failover TAF configuredNOTE:332792.1 - ORA-04061 error relating to SYS.DBMS_PRVTAQIP reported when setting up StatspackNOTE:333068.1 - ORA-23603: Streams Enqueue Aborted Eue To Low SGANOTE:335516.1 - Master Note for Streams Performance RecommendationsNOTE:353325.1 - ORA-24056: Internal inconsistency for QUEUE and destination NOTE:353754.1 - Streams Messaging Propagation Fails between Single and Multi-byte Charactersets when using Chararacter Length Semantics in the ADT.NOTE:359971.1 - STREAMS propagation to Primary of physical Standby configuation errors with Ora-01033, Ora-02068NOTE:363496.1 - Ora-25315 Propagating on RAC StreamsNOTE:365093.1 - ORA-07445 [kwqppay2aqe()+7360] reported on Propagation of a Transformed MessageNOTE:368237.1 - Unable to Unschedule Propagation. Streams Queue is InvalidNOTE:368912.1 - Queue to Queue Propagation Schedule encountered ORA-12514 in a RAC environmentNOTE:421237.1 - ORA-600 [KWQBMCRCPTS101] reported by a Qmon slave process after dropping a Streams PropagationNOTE:436332.1 - dbms_propagation_adm.stop_propagation hangsNOTE:437838.1 - Streams Specific PatchesNOTE:460471.1 - Propagation Blocked by Qmon Process - Streams_queue_table / 'library cache lock' waitsNOTE:463820.1 - Streams Combined Capture and Apply in 11gNOTE:553017.1 - Stream Propagation Process Errors Ora-4052 Ora-6554 From 11g To 10201NOTE:556309.1 - Changing Propagation/ queue_to_queue : false -> true does does not work; no LCRs propagatedNOTE:564649.1 - ORA-02068/ORA-03114/ORA-03113 Errors From Streams Propagation Process - Remote Database is Available and Unschedule/Reschedule Does Not ResolveNOTE:566622.1 - ORA-22275 when propagating >4K AQ$_JMS_TEXT_MESSAGEs from 9.2.0.8 to 10.2.0.1NOTE:727389.1 - Propagation Fails With ORA-12528NOTE:730036.1 - Overview for Troubleshooting Streams Performance IssuesNOTE:730911.1 - ORA-4063 Is Reported After Dropping Negative Prop.RulesetNOTE:731292.1 - ORA-25215 Reported On Local Propagation When Using Transformation with ANYDATA queue tablesNOTE:731539.1 - ORA-29268: HTTP client error 401 Unauthorized Error when the AQ Servlet attempts to Propagate a message via HTTPNOTE:745601.1 - ORA-23603 'STREAMS enqueue aborted due to low SGA' Error from Streams Propagation, and V$STREAMS_CAPTURE.STATE Hanging on 'Enqueuing Message'NOTE:749181.1 - How to Recover Streams After Dropping PropagationNOTE:780733.1 - Streams Propagation Tuning with Network ParametersNOTE:787367.1 - ORA-22275 reported on Propagating Messages with LOB component when propagating between 10.1 and 10.2NOTE:808136.1 - How to clear the old errors from DBA_PROPAGATION view ?NOTE:827184.1 - AQ Propagation with CLOB data types Fails with ORA-22990NOTE:827473.1 - How to alter propagation from queue_to_queue to queue_to_dblinkNOTE:839568.1 - Propagation failing with error: ORA-01536: space quota exceeded for tablespace ''NOTE:846297.1 - AQ Propagation Fails : ORA-00600[kope2upic2954] or Ora-00600[Kghsstream_copyn]NOTE:944846.1 - Streams Propagation Fails Ora-7445 [kohrsmc]

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