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• Differences Between NHibernate and Entity Framework

  - by Ricardo Peres

  Introduction NHibernate and Entity Framework are two of the most popular O/RM frameworks on the .NET world. Although they share some functionality, there are some aspects on which they are quite different. This post will describe this differences and will hopefully help you get started with the one you know less. Mind you, this is a personal selection of features to compare, it is by no way an exhaustive list. History First, a bit of history. NHibernate is an open-source project that was first ported from Java’s venerable Hibernate framework, one of the first O/RM frameworks, but nowadays it is not tied to it, for example, it has .NET specific features, and has evolved in different ways from those of its Java counterpart. Current version is 3.3, with 3.4 on the horizon. It currently targets .NET 3.5, but can be used as well in .NET 4, it only makes no use of any of its specific functionality. You can find its home page at NHForge. Entity Framework 1 came out with .NET 3.5 and is now on its second major version, despite being version 4. Code First sits on top of it and but came separately and will also continue to be released out of line with major .NET distributions. It is currently on version 4.3.1 and version 5 will be released together with .NET Framework 4.5. All versions will target the current version of .NET, at the time of their release. Its home location is located at MSDN. Architecture In NHibernate, there is a separation between the Unit of Work and the configuration and model instances. You start off by creating a Configuration object, where you specify all global NHibernate settings such as the database and dialect to use, the batch sizes, the mappings, etc, then you build an ISessionFactory from it. The ISessionFactory holds model and metadata that is tied to a particular database and to the settings that came from the Configuration object, and, there will typically be only one instance of each in a process. Finally, you create instances of ISession from the ISessionFactory, which is the NHibernate representation of the Unit of Work and Identity Map. This is a lightweight object, it basically opens and closes a database connection as required and keeps track of the entities associated with it. ISession objects are cheap to create and dispose, because all of the model complexity is stored in the ISessionFactory and Configuration objects. As for Entity Framework, the ObjectContext/DbContext holds the configuration, model and acts as the Unit of Work, holding references to all of the known entity instances. This class is therefore not lightweight as its NHibernate counterpart and it is not uncommon to see examples where an instance is cached on a field. Mappings Both NHibernate and Entity Framework (Code First) support the use of POCOs to represent entities, no base classes are required (or even possible, in the case of NHibernate). As for mapping to and from the database, NHibernate supports three types of mappings: XML-based, which have the advantage of not tying the entity classes to a particular O/RM; the XML files can be deployed as files on the file system or as embedded resources in an assembly; Attribute-based, for keeping both the entities and database details on the same place at the expense of polluting the entity classes with NHibernate-specific attributes; Strongly-typed code-based, which allows dynamic creation of the model and strongly typing it, so that if, for example, a property name changes, the mapping will also be updated. Entity Framework can use: Attribute-based (although attributes cannot express all of the available possibilities – for example, cascading); Strongly-typed code mappings. Database Support With NHibernate you can use mostly any database you want, including: SQL Server; SQL Server Compact; SQL Server Azure; Oracle; DB2; PostgreSQL; MySQL; Sybase Adaptive Server/SQL Anywhere; Firebird; SQLLite; Informix; Any through OLE DB; Any through ODBC. Out of the box, Entity Framework only supports SQL Server, but a number of providers exist, both free and commercial, for some of the most used databases, such as Oracle and MySQL. See a list here. Inheritance Strategies Both NHibernate and Entity Framework support the three canonical inheritance strategies: Table Per Type Hierarchy (Single Table Inheritance), Table Per Type (Class Table Inheritance) and Table Per Concrete Type (Concrete Table Inheritance). Associations Regarding associations, both support one to one, one to many and many to many. However, NHibernate offers far more collection types: Bags of entities or values: unordered, possibly with duplicates; Lists of entities or values: ordered, indexed by a number column; Maps of entities or values: indexed by either an entity or any value; Sets of entities or values: unordered, no duplicates; Arrays of entities or values: indexed, immutable. Querying NHibernate exposes several querying APIs: LINQ is probably the most used nowadays, and really does not need to be introduced; Hibernate Query Language (HQL) is a database-agnostic, object-oriented SQL-alike language that exists since NHibernate’s creation and still offers the most advanced querying possibilities; well suited for dynamic queries, even if using string concatenation; Criteria API is an implementation of the Query Object pattern where you create a semi-abstract conceptual representation of the query you wish to execute by means of a class model; also a good choice for dynamic querying; Query Over offers a similar API to Criteria, but using strongly-typed LINQ expressions instead of strings; for this, although more refactor-friendlier that Criteria, it is also less suited for dynamic queries; SQL, including stored procedures, can also be used; Integration with Lucene.NET indexer is available. As for Entity Framework: LINQ to Entities is fully supported, and its implementation is considered very complete; it is the API of choice for most developers; Entity-SQL, HQL’s counterpart, is also an object-oriented, database-independent querying language that can be used for dynamic queries; SQL, of course, is also supported. Caching Both NHibernate and Entity Framework, of course, feature first-level cache. NHibernate also supports a second-level cache, that can be used among multiple ISessionFactorys, even in different processes/machines: Hashtable (in-memory); SysCache (uses ASP.NET as the cache provider); SysCache2 (same as above but with support for SQL Server SQL Dependencies); Prevalence; SharedCache; Memcached; Redis; NCache; Appfabric Caching. Out of the box, Entity Framework does not have any second-level cache mechanism, however, there are some public samples that show how we can add this. ID Generators NHibernate supports different ID generation strategies, coming from the database and otherwise: Identity (for SQL Server, MySQL, and databases who support identity columns); Sequence (for Oracle, PostgreSQL, and others who support sequences); Trigger-based; HiLo; Sequence HiLo (for databases that support sequences); Several GUID flavors, both in GUID as well as in string format; Increment (for single-user uses); Assigned (must know what you’re doing); Sequence-style (either uses an actual sequence or a single-column table); Table of ids; Pooled (similar to HiLo but stores high values in a table); Native (uses whatever mechanism the current database supports, identity or sequence). Entity Framework only supports: Identity generation; GUIDs; Assigned values. Properties NHibernate supports properties of entity types (one to one or many to one), collections (one to many or many to many) as well as scalars and enumerations. It offers a mechanism for having complex property types generated from the database, which even include support for querying. It also supports properties originated from SQL formulas. Entity Framework only supports scalars, entity types and collections. Enumerations support will come in the next version. Events and Interception NHibernate has a very rich event model, that exposes more than 20 events, either for synchronous pre-execution or asynchronous post-execution, including: Pre/Post-Load; Pre/Post-Delete; Pre/Post-Insert; Pre/Post-Update; Pre/Post-Flush. It also features interception of class instancing and SQL generation. As for Entity Framework, only two events exist: ObjectMaterialized (after loading an entity from the database); SavingChanges (before saving changes, which include deleting, inserting and updating). Tracking Changes For NHibernate as well as Entity Framework, all changes are tracked by their respective Unit of Work implementation. Entities can be attached and detached to it, Entity Framework does, however, also support self-tracking entities. Optimistic Concurrency Control NHibernate supports all of the imaginable scenarios: SQL Server’s ROWVERSION; Oracle’s ORA_ROWSCN; A column containing date and time; A column containing a version number; All/dirty columns comparison. Entity Framework is more focused on Entity Framework, so it only supports: SQL Server’s ROWVERSION; Comparing all/some columns. Batching NHibernate has full support for insertion batching, but only if the ID generator in use is not database-based (for example, it cannot be used with Identity), whereas Entity Framework has no batching at all. Cascading Both support cascading for collections and associations: when an entity is deleted, their conceptual children are also deleted. NHibernate also offers the possibility to set the foreign key column on children to NULL instead of removing them. Flushing Changes NHibernate’s ISession has a FlushMode property that can have the following values: Auto: changes are sent to the database when necessary, for example, if there are dirty instances of an entity type, and a query is performed against this entity type, or if the ISession is being disposed; Commit: changes are sent when committing the current transaction; Never: changes are only sent when explicitly calling Flush(). As for Entity Framework, changes have to be explicitly sent through a call to AcceptAllChanges()/SaveChanges(). Lazy Loading NHibernate supports lazy loading for Associated entities (one to one, many to one); Collections (one to many, many to many); Scalar properties (thing of BLOBs or CLOBs). Entity Framework only supports lazy loading for: Associated entities; Collections. Generating and Updating the Database Both NHibernate and Entity Framework Code First (with the Migrations API) allow creating the database model from the mapping and updating it if the mapping changes. Extensibility As you can guess, NHibernate is far more extensible than Entity Framework. Basically, everything can be extended, from ID generation, to LINQ to SQL transformation, HQL native SQL support, custom column types, custom association collections, SQL generation, supported databases, etc. With Entity Framework your options are more limited, at least, because practically no information exists as to what can be extended/changed. It features a provider model that can be extended to support any database. Integration With Other Microsoft APIs and Tools When it comes to integration with Microsoft technologies, it will come as no surprise that Entity Framework offers the best support. For example, the following technologies are fully supported: ASP.NET (through the EntityDataSource); ASP.NET Dynamic Data; WCF Data Services; WCF RIA Services; Visual Studio (through the integrated designer). Documentation This is another point where Entity Framework is superior: NHibernate lacks, for starters, an up to date API reference synchronized with its current version. It does have a community mailing list, blogs and wikis, although not much used. Entity Framework has a number of resources on MSDN and, of course, several forums and discussion groups exist. Conclusion Like I said, this is a personal list. I may come as a surprise to some that Entity Framework is so behind NHibernate in so many aspects, but it is true that NHibernate is much older and, due to its open-source nature, is not tied to product-specific timeframes and can thus evolve much more rapidly. I do like both, and I chose whichever is best for the job I have at hands. I am looking forward to the changes in EF5 which will add significant value to an already interesting product. So, what do you think? Did I forget anything important or is there anything else worth talking about? Looking forward for your comments!

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• Creating ASP.NET MVC Negotiated Content Results

  - by Rick Strahl

  In a recent ASP.NET MVC application I’m involved with, we had a late in the process request to handle Content Negotiation: Returning output based on the HTTP Accept header of the incoming HTTP request. This is standard behavior in ASP.NET Web API but ASP.NET MVC doesn’t support this functionality directly out of the box. Another reason this came up in discussion is last week’s announcements of ASP.NET vNext, which seems to indicate that ASP.NET Web API is not going to be ported to the cloud version of vNext, but rather be replaced by a combined version of MVC and Web API. While it’s not clear what new API features will show up in this new framework, it’s pretty clear that the ASP.NET MVC style syntax will be the new standard for all the new combined HTTP processing framework. Why negotiated Content? Content negotiation is one of the key features of Web API even though it’s such a relatively simple thing. But it’s also something that’s missing in MVC and once you get used to automatically having your content returned based on Accept headers it’s hard to go back to manually having to create separate methods for different output types as you’ve had to with Microsoft server technologies all along (yes, yes I know other frameworks – including my own – have done this for years but for in the box features this is relatively new from Web API). As a quick review,  Accept Header content negotiation works off the request’s HTTP Accept header:POST http://localhost/mydailydosha/Editable/NegotiateContent HTTP/1.1 Content-Type: application/json Accept: application/json Host: localhost Content-Length: 76 Pragma: no-cache { ElementId: "header", PageName: "TestPage", Text: "This is a nice header" } If I make this request I would expect to get back a JSON result based on my application/json Accept header. To request XML  I‘d just change the accept header:Accept: text/xml and now I’d expect the response to come back as XML. Now this only works with media types that the server can process. In my case here I need to handle JSON, XML, HTML (using Views) and Plain Text. HTML results might need more than just a data return – you also probably need to specify a View to render the data into either by specifying the view explicitly or by using some sort of convention that can automatically locate a view to match. Today ASP.NET MVC doesn’t support this sort of automatic content switching out of the box. Unfortunately, in my application scenario we have an application that started out primarily with an AJAX backend that was implemented with JSON only. So there are lots of JSON results like this:[Route("Customers")] public ActionResult GetCustomers() { return Json(repo.GetCustomers(),JsonRequestBehavior.AllowGet); } These work fine, but they are of course JSON specific. Then a couple of weeks ago, a requirement came in that an old desktop application needs to also consume this API and it has to use XML to do it because there’s no JSON parser available for it. Ooops – stuck with JSON in this case. While it would have been easy to add XML specific methods I figured it’s easier to add basic content negotiation. And that’s what I show in this post. Missteps – IResultFilter, IActionFilter My first attempt at this was to use IResultFilter or IActionFilter which look like they would be ideal to modify result content after it’s been generated using OnResultExecuted() or OnActionExecuted(). Filters are great because they can look globally at all controller methods or individual methods that are marked up with the Filter’s attribute. But it turns out these filters don’t work for raw POCO result values from Action methods. What we wanted to do for API calls is get back to using plain .NET types as results rather than result actions. That is  you write a method that doesn’t return an ActionResult, but a standard .NET type like this:public Customer UpdateCustomer(Customer cust) { … do stuff to customer :-) return cust; } Unfortunately both OnResultExecuted and OnActionExecuted receive an MVC ContentResult instance from the POCO object. MVC basically takes any non-ActionResult return value and turns it into a ContentResult by converting the value using .ToString(). Ugh. The ContentResult itself doesn’t contain the original value, which is lost AFAIK with no way to retrieve it. So there’s no way to access the raw customer object in the example above. Bummer. Creating a NegotiatedResult This leaves mucking around with custom ActionResults. ActionResults are MVC’s standard way to return action method results – you basically specify that you would like to render your result in a specific format. Common ActionResults are ViewResults (ie. View(vn,model)), JsonResult, RedirectResult etc. They work and are fairly effective and work fairly well for testing as well as it’s the ‘standard’ interface to return results from actions. The problem with the this is mainly that you’re explicitly saying that you want a specific result output type. This works well for many things, but sometimes you do want your result to be negotiated. My first crack at this solution here is to create a simple ActionResult subclass that looks at the Accept header and based on that writes the output. I need to support JSON and XML content and HTML as well as text – so effectively 4 media types: application/json, text/xml, text/html and text/plain. Everything else is passed through as ContentResult – which effecively returns whatever .ToString() returns. Here’s what the NegotiatedResult usage looks like:public ActionResult GetCustomers() { return new NegotiatedResult(repo.GetCustomers()); } public ActionResult GetCustomer(int id) { return new NegotiatedResult("Show", repo.GetCustomer(id)); } There are two overloads of this method – one that returns just the raw result value and a second version that accepts an optional view name. The second version returns the Razor view specified only if text/html is requested – otherwise the raw data is returned. This is useful in applications where you have an HTML front end that can also double as an API interface endpoint that’s using the same model data you send to the View. For the application I mentioned above this was another actual use-case we needed to address so this was a welcome side effect of creating a custom ActionResult. There’s also an extension method that directly attaches a Negotiated() method to the controller using the same syntax:public ActionResult GetCustomers() { return this.Negotiated(repo.GetCustomers()); } public ActionResult GetCustomer(int id) { return this.Negotiated("Show",repo.GetCustomer(id)); } Using either of these mechanisms now allows you to return JSON, XML, HTML or plain text results depending on the Accept header sent. Send application/json you get just the Customer JSON data. Ditto for text/xml and XML data. Pass text/html for the Accept header and the "Show.cshtml" Razor view is rendered passing the result model data producing final HTML output. While this isn’t as clean as passing just POCO objects back as I had intended originally, this approach fits better with how MVC action methods are intended to be used and we get the bonus of being able to specify a View to render (optionally) for HTML. How does it work An ActionResult implementation is pretty straightforward. You inherit from ActionResult and implement the ExecuteResult method to send your output to the ASP.NET output stream. ActionFilters are an easy way to effectively do post processing on ASP.NET MVC controller actions just before the content is sent to the output stream, assuming your specific action result was used. Here’s the full code to the NegotiatedResult class (you can also check it out on GitHub):/// <summary> /// Returns a content negotiated result based on the Accept header. /// Minimal implementation that works with JSON and XML content, /// can also optionally return a view with HTML. /// </summary> /// <example> /// // model data only /// public ActionResult GetCustomers() /// { /// return new NegotiatedResult(repo.Customers.OrderBy( c=> c.Company) ) /// } /// // optional view for HTML /// public ActionResult GetCustomers() /// { /// return new NegotiatedResult("List", repo.Customers.OrderBy( c=> c.Company) ) /// } /// </example> public class NegotiatedResult : ActionResult { /// <summary> /// Data stored to be 'serialized'. Public /// so it's potentially accessible in filters. /// </summary> public object Data { get; set; } /// <summary> /// Optional name of the HTML view to be rendered /// for HTML responses /// </summary> public string ViewName { get; set; } public static bool FormatOutput { get; set; } static NegotiatedResult() { FormatOutput = HttpContext.Current.IsDebuggingEnabled; } /// <summary> /// Pass in data to serialize /// </summary> /// <param name="data">Data to serialize</param> public NegotiatedResult(object data) { Data = data; } /// <summary> /// Pass in data and an optional view for HTML views /// </summary> /// <param name="data"></param> /// <param name="viewName"></param> public NegotiatedResult(string viewName, object data) { Data = data; ViewName = viewName; } public override void ExecuteResult(ControllerContext context) { if (context == null) throw new ArgumentNullException("context"); HttpResponseBase response = context.HttpContext.Response; HttpRequestBase request = context.HttpContext.Request; // Look for specific content types if (request.AcceptTypes.Contains("text/html")) { response.ContentType = "text/html"; if (!string.IsNullOrEmpty(ViewName)) { var viewData = context.Controller.ViewData; viewData.Model = Data; var viewResult = new ViewResult { ViewName = ViewName, MasterName = null, ViewData = viewData, TempData = context.Controller.TempData, ViewEngineCollection = ((Controller)context.Controller).ViewEngineCollection }; viewResult.ExecuteResult(context.Controller.ControllerContext); } else response.Write(Data); } else if (request.AcceptTypes.Contains("text/plain")) { response.ContentType = "text/plain"; response.Write(Data); } else if (request.AcceptTypes.Contains("application/json")) { using (JsonTextWriter writer = new JsonTextWriter(response.Output)) { var settings = new JsonSerializerSettings(); if (FormatOutput) settings.Formatting = Newtonsoft.Json.Formatting.Indented; JsonSerializer serializer = JsonSerializer.Create(settings); serializer.Serialize(writer, Data); writer.Flush(); } } else if (request.AcceptTypes.Contains("text/xml")) { response.ContentType = "text/xml"; if (Data != null) { using (var writer = new XmlTextWriter(response.OutputStream, new UTF8Encoding())) { if (FormatOutput) writer.Formatting = System.Xml.Formatting.Indented; XmlSerializer serializer = new XmlSerializer(Data.GetType()); serializer.Serialize(writer, Data); writer.Flush(); } } } else { // just write data as a plain string response.Write(Data); } } } /// <summary> /// Extends Controller with Negotiated() ActionResult that does /// basic content negotiation based on the Accept header. /// </summary> public static class NegotiatedResultExtensions { /// <summary> /// Return content-negotiated content of the data based on Accept header. /// Supports: /// application/json - using JSON.NET /// text/xml - Xml as XmlSerializer XML /// text/html - as text, or an optional View /// text/plain - as text /// </summary> /// <param name="controller"></param> /// <param name="data">Data to return</param> /// <returns>serialized data</returns> /// <example> /// public ActionResult GetCustomers() /// { /// return this.Negotiated( repo.Customers.OrderBy( c=> c.Company) ) /// } /// </example> public static NegotiatedResult Negotiated(this Controller controller, object data) { return new NegotiatedResult(data); } /// <summary> /// Return content-negotiated content of the data based on Accept header. /// Supports: /// application/json - using JSON.NET /// text/xml - Xml as XmlSerializer XML /// text/html - as text, or an optional View /// text/plain - as text /// </summary> /// <param name="controller"></param> /// <param name="viewName">Name of the View to when Accept is text/html</param> /// /// <param name="data">Data to return</param> /// <returns>serialized data</returns> /// <example> /// public ActionResult GetCustomers() /// { /// return this.Negotiated("List", repo.Customers.OrderBy( c=> c.Company) ) /// } /// </example> public static NegotiatedResult Negotiated(this Controller controller, string viewName, object data) { return new NegotiatedResult(viewName, data); } } Output Generation – JSON and XML Generating output for XML and JSON is simple – you use the desired serializer and off you go. Using XmlSerializer and JSON.NET it’s just a handful of lines each to generate serialized output directly into the HTTP output stream. Please note this implementation uses JSON.NET for its JSON generation rather than the default JavaScriptSerializer that MVC uses which I feel is an additional bonus to implementing this custom action. I’d already been using a custom JsonNetResult class previously, but now this is just rolled into this custom ActionResult. Just keep in mind that JSON.NET outputs slightly different JSON for certain things like collections for example, so behavior may change. One addition to this implementation might be a flag to allow switching the JSON serializer. Html View Generation Html View generation actually turned out to be easier than anticipated. Initially I used my generic ASP.NET ViewRenderer Class that can render MVC views from any ASP.NET application. However it turns out since we are executing inside of an active MVC request there’s an easier way: We can simply create a custom ViewResult and populate its members and then execute it. The code in text/html handling code that renders the view is simply this:response.ContentType = "text/html"; if (!string.IsNullOrEmpty(ViewName)) { var viewData = context.Controller.ViewData; viewData.Model = Data; var viewResult = new ViewResult { ViewName = ViewName, MasterName = null, ViewData = viewData, TempData = context.Controller.TempData, ViewEngineCollection = ((Controller)context.Controller).ViewEngineCollection }; viewResult.ExecuteResult(context.Controller.ControllerContext); } else response.Write(Data); which is a neat and easy way to render a Razor view assuming you have an active controller that’s ready for rendering. Sweet – dependency removed which makes this class self-contained without any external dependencies other than JSON.NET. Summary While this isn’t exactly a new topic, it’s the first time I’ve actually delved into this with MVC. I’ve been doing content negotiation with Web API and prior to that with my REST library. This is the first time it’s come up as an issue in MVC. But as I have worked through this I find that having a way to specify both HTML Views *and* JSON and XML results from a single controller certainly is appealing to me in many situations as we are in this particular application returning identical data models for each of these operations. Rendering content negotiated views is something that I hope ASP.NET vNext will provide natively in the combined MVC and WebAPI model, but we’ll see how this actually will be implemented. In the meantime having a custom ActionResult that provides this functionality is a workable and easily adaptable way of handling this going forward. Whatever ends up happening in ASP.NET vNext the abstraction can probably be changed to support the native features of the future. Anyway I hope some of you found this useful if not for direct integration then as insight into some of the rendering logic that MVC uses to get output into the HTTP stream… Related Resources Latest Version of NegotiatedResult.cs on GitHub Understanding Action Controllers Rendering ASP.NET Views To String© Rick Strahl, West Wind Technologies, 2005-2014Posted in MVC  ASP.NET  HTTP   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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• MINSCN?Cache Fusion Read Consistent

  - by Liu Maclean(???)

  ????? ???Ask Maclean Home ???  RAC ? Past Image PI????, ?????????,???11.2.0.3 2 Node RAC??????????: SQL> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production PL/SQL Release 11.2.0.3.0 - Production CORE 11.2.0.3.0 Production TNS for Linux: Version 11.2.0.3.0 - Production NLSRTL Version 11.2.0.3.0 - Production SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com SQL> drop table test purge; Table dropped. SQL> alter system flush buffer_cache; System altered. SQL> create table test(id number); insert into test values(1); insert into test values(2); commit; /* ???? rowid??TEST????2????????? */ select dbms_rowid.rowid_block_number(rowid),dbms_rowid.rowid_relative_fno(rowid) from test; DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) ------------------------------------ ------------------------------------                                89233                                    1                                89233                                    1 SQL> alter system flush buffer_cache; System altered. Instance 1 Session A ??UPDATE??: SQL> update test set id=id+1 where id=1; 1 row updated. Instance 1 Session B ??x$BH buffer header?? ?? ??Buffer??? SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;      STATE CR_SCN_BAS ---------- ----------          1          0          3    1227595 X$BH ??? STATE????Buffer???, ???????: STATE NUMBER KCBBHFREE 0 buffer free KCBBHEXLCUR 1 buffer current (and if DFS locked X) KCBBHSHRCUR 2 buffer current (and if DFS locked S) KCBBHCR 3 buffer consistant read KCBBHREADING 4 Being read KCBBHMRECOVERY 5 media recovery (current & special) KCBBHIRECOVERY 6 Instance recovery (somewhat special) ????????????? : state =1 Xcurrent ? state=2 Scurrent ? state=3 CR ??? Instance 2  ?? ????????????? ,???? gc current block 2 way  ??Current Block ??? Instance 2, ?? Instance 1 ??”Current Block” Convert ? Past Image: Instance 2 Session C SQL> update test set id=id+1 where id=2; 1 row updated. Instance 2 Session D SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 1 0 3 1227641 3 1227638 STATE =1 ?Xcurrent block???? Instance 2 , ??? Instance 1 ??? GC??: Instance 1 Session B SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;      STATE CR_SCN_BAS ---------- ----------          3    1227641          3    1227638          8          0          3    1227595 ???????, ??????Instance 1??session A????TEST??SELECT??? ,????? 3? State=3?CR ? ??????1?: Instance 1 session A ?????UPDATE? session SQL> alter session set events '10046 trace name context forever,level 8:10708 trace name context forever,level 103: trace[rac.*] disk high'; Session altered. SQL> select * from test;         ID ----------          2          2 select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;       STATE CR_SCN_BAS ---------- ----------          3    1227716          3    1227713          8          0 ?????????v$BH ????CR????,?????SELECT??? CR????????,???????? ?????????? ??X$BH?????? , ?????CR??SCN Version???: 1227641?1227638?1227595, ?SELECT?????? 2???SCN version?CR? 1227716? 1227713 ???, Oracle????????? ?????????SELECT??????event 10708? rac.*???TRACE,??????TRACE??: PARSING IN CURSOR #140444679938584 len=337 dep=1 uid=0 oct=3 lid=0 tim=1335698913632292 hv=3345277572 ad='bc0e68c8' sqlid='baj7tjm3q9sn4' SELECT /* OPT_DYN_SAMP */ /*+ ALL_ROWS IGNORE_WHERE_CLAUSE NO_PARALLEL(SAMPLESUB) opt_param('parallel_execution_enabled', 'false') NO_PARALLEL_INDEX(SAMPLESUB) NO_SQL_TUNE */ NVL(SUM(C1),0), NVL(SUM(C2),0) FROM (SELECT /*+ NO_PARALLEL("TEST") FULL("TEST") NO_PARALLEL_INDEX("TEST") */ 1 AS C1, 1 AS C2 FROM "SYS"."TEST" "TEST") SAMPLESUB END OF STMT PARSE #140444679938584:c=1000,e=27630,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=1,plh=1950795681,tim=1335698913632252 EXEC #140444679938584:c=0,e=44,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=1950795681,tim=1335698913632390 *** 2012-04-29 07:28:33.632 kclscrs: req=0 block=1/89233 *** 2012-04-29 07:28:33.632 kclscrs: bid=1:3:1:0:7:80:1:0:4:0:0:0:1:2:4:1:26:0:0:0:70:1a:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:4:3:2:1:2:0:3f:0:1c:86:2d:4:0:0:0:0:a2:3c:7c:b:70:1a:0:0:0:0:1:0:7a:f8:76:1d:1:2:dc:5:a9:fe:17:75:0:0:0:0:0:0:0:0:0:0:0:0:63:e5:0:0:0:0:0:0:10:0:0:0 2012-04-29 07:28:33.632578 : kjbcrc[0x15c91.1 76896.0][9] 2012-04-29 07:28:33.632616 : GSIPC:GMBQ: buff 0xba1e8f90, queue 0xbb79f278, pool 0x60013fa0, freeq 1, nxt 0xbb79f278, prv 0xbb79f278 2012-04-29 07:28:33.632634 : kjbmscrc(0x15c91.1)seq 0x2 reqid=0x1c(shadow 0xb4bb4458,reqid x1c)mas@2(infosz 200)(direct 1) 2012-04-29 07:28:33.632654 : kjbsentscn[0x0.12bbc1][to 2] 2012-04-29 07:28:33.632669 : GSIPC:SENDM: send msg 0xba1e9000 dest x20001 seq 24026 type 32 tkts xff0000 mlen x17001a0 2012-04-29 07:28:33.633385 : GSIPC:KSXPCB: msg 0xba1e9000 status 30, type 32, dest 2, rcvr 1 *** 2012-04-29 07:28:33.633 kclwcrs: wait=0 tm=689 *** 2012-04-29 07:28:33.633 kclwcrs: got 1 blocks from ksxprcv WAIT #140444679938584: nam='gc cr block 2-way' ela= 689 p1=1 p2=89233 p3=1 obj#=76896 tim=1335698913633418 2012-04-29 07:28:33.633490 : kjbcrcomplete[0x15c91.1 76896.0][0] 2012-04-29 07:28:33.633510 : kjbrcvdscn[0x0.12bbc1][from 2][idx 2012-04-29 07:28:33.633527 : kjbrcvdscn[no bscn <= rscn 0x0.12bbc1][from 2] *** 2012-04-29 07:28:33.633 kclwcrs: req=0 typ=cr(2) wtyp=2hop tm=689 ??TRACE???? ?????????TEST??????, ???????Dynamic Sampling?????,???????TEST?? CR???,???????’gc cr block 2-way’ ??: 2012-04-29 07:28:33.632654 : kjbsentscn[0x0.12bbc1][to 2] 12bbc1= 1227713  ???X$BH????CR???,kjbsentscn[0x0.12bbc1][to 2] ????? ? Instance 2 ???SCN=12bbc1=1227713   DBA=0x15c91.1 76896.0 ?  CR Request(obj#=76896) ??kjbrcvdscn????? [no bscn <= rscn 0x0.12bbc1][from 2] ,??? ??receive? SCN Version =12bbc1 ???Best Version CR Server Arch ??????????????????SELECT??: PARSING IN CURSOR #140444682869592 len=18 dep=0 uid=0 oct=3 lid=0 tim=1335698913635874 hv=1689401402 ad='b1a188f0' sqlid='c99yw1xkb4f1u' select * from test END OF STMT PARSE #140444682869592:c=4999,e=34017,p=0,cr=7,cu=0,mis=1,r=0,dep=0,og=1,plh=1357081020,tim=1335698913635870 EXEC #140444682869592:c=0,e=23,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=1357081020,tim=1335698913635939 WAIT #140444682869592: nam='SQL*Net message to client' ela= 7 driver id=1650815232 #bytes=1 p3=0 obj#=0 tim=1335698913636071 *** 2012-04-29 07:28:33.636 kclscrs: req=0 block=1/89233 *** 2012-04-29 07:28:33.636 kclscrs: bid=1:3:1:0:7:83:1:0:4:0:0:0:1:2:4:1:26:0:0:0:70:1a:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:0:4:3:2:1:2:0:2:0:1c:86:2d:4:0:0:0:0:a2:3c:7c:b:70:1a:0:0:0:0:1:0:7d:f8:76:1d:1:2:dc:5:a9:fe:17:75:0:0:0:0:0:0:0:0:0:0:0:0:63:e5:0:0:0:0:0:0:10:0:0:0 2012-04-29 07:28:33.636209 : kjbcrc[0x15c91.1 76896.0][9] 2012-04-29 07:28:33.636228 : GSIPC:GMBQ: buff 0xba0e5d50, queue 0xbb79f278, pool 0x60013fa0, freeq 1, nxt 0xbb79f278, prv 0xbb79f278 2012-04-29 07:28:33.636244 : kjbmscrc(0x15c91.1)seq 0x3 reqid=0x1d(shadow 0xb4bb4458,reqid x1d)mas@2(infosz 200)(direct 1) 2012-04-29 07:28:33.636252 : kjbsentscn[0x0.12bbc4][to 2] 2012-04-29 07:28:33.636358 : GSIPC:SENDM: send msg 0xba0e5dc0 dest x20001 seq 24029 type 32 tkts xff0000 mlen x17001a0 2012-04-29 07:28:33.636861 : GSIPC:KSXPCB: msg 0xba0e5dc0 status 30, type 32, dest 2, rcvr 1 *** 2012-04-29 07:28:33.637 kclwcrs: wait=0 tm=865 *** 2012-04-29 07:28:33.637 kclwcrs: got 1 blocks from ksxprcv WAIT #140444682869592: nam='gc cr block 2-way' ela= 865 p1=1 p2=89233 p3=1 obj#=76896 tim=1335698913637294 2012-04-29 07:28:33.637356 : kjbcrcomplete[0x15c91.1 76896.0][0] 2012-04-29 07:28:33.637374 : kjbrcvdscn[0x0.12bbc4][from 2][idx 2012-04-29 07:28:33.637389 : kjbrcvdscn[no bscn <= rscn 0x0.12bbc4][from 2] *** 2012-04-29 07:28:33.637 kclwcrs: req=0 typ=cr(2) wtyp=2hop tm=865 ???, “SELECT * FROM TEST”??????’gc cr block 2-way’??:2012-04-29 07:28:33.637374 : kjbrcvdscn[0x0.12bbc4][from 2][idx 2012-04-29 07:28:33.637389 : kjbrcvdscn[no bscn ??Foreground Process? Remote LMS??got?? SCN=1227716 Version?CR, ??? ?????X$BH ?????scn??? ??????????Instance 1????2?SCN???CR?, ???????????Instance 1 Buffer Cache?? ??SCN Version ???CR ??????? ?????????: SQL> alter system set "_enable_minscn_cr"=false scope=spfile; System altered. SQL> alter system set "_db_block_max_cr_dba"=20 scope=spfile; System altered. SQL> startup force; ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance ORACLE instance started. Total System Global Area 1570009088 bytes Fixed Size 2228704 bytes Variable Size 989859360 bytes Database Buffers 570425344 bytes Redo Buffers 7495680 bytes Database mounted. Database opened. ???? “_enable_minscn_cr”=false ? “_db_block_max_cr_dba”=20 ???RAC????, ??????: ?Instance 2 Session C ?update??????? ?????Instance 1 ????? ,????Instance 1?Request CR SQL> update test set id=id+1 where id=2; -- Instance 2 1 row updated. SQL> select * From test; -- Instance 1 ID ---------- 1 2 ??? Instance 1? X$BH?? select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0;  STATE CR_SCN_BAS ---------- ---------- 3 1273080 3 1273071 3 1273041 3 1273039 8 0 SQL> update test set id=id+1 where id=3; 1 row updated. SQL> select * From test; ID ---------- 1 2 SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1273091 3 1273080 3 1273071 3 1273041 3 1273039 8 0 ................... SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1273793 3 1273782 3 1273780 3 1273769 3 1273734 3 1273715 3 1273691 3 1273679 3 1273670 3 1273643 3 1273635 3 1273623 3 1273106 3 1273091 3 1273080 3 1273071 3 1273041 3 1273039 3 1273033 19 rows selected. SQL> select state,cr_scn_bas from x$bh where file#=1 and dbablk=89233 and state!=0; STATE CR_SCN_BAS ---------- ---------- 3 1274993 ????? ???? “_enable_minscn_cr”(enable/disable minscn optimization for CR)=false ? “_db_block_max_cr_dba”=20 (Maximum Allowed Number of CR buffers per dba) 2? ??? ????? Instance 1 ??????????? ?? 19????CR?? “_enable_minscn_cr”?11g??????????,???Oracle????CR????SCN,?Foreground Process Receive????????????(SCN??)?SCN Version CR Block??????CBC?? SCN??????CR? , ?????????Buffer Cache??????? ????SCN Version?CR????,????? ?????????? ?????Snap_Scn ?? SCN?? ?????????Current SCN, ??????CR??????????????????????, ????Buffer Cache? ?????????? CR?????????, ?????? “_db_block_max_cr_dba” ???????, ???????????20 ,??????Buffer Cache?????19????CR?; ???”_db_block_max_cr_dba” ???????6 , ?????Buffer cache????????CR ???????6?? ??”_enable_minscn_cr” ??CR???MINSCN ??????, ?????????CR???????, ????? Foreground Process??????CR Request , ?? Holder Instance LMS ?build?? BEST CR ??, ?????????

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• CBO????????

  - by Liu Maclean(???)

  ???Itpub????????CBO??????????, ????????: SQL> create table maclean1 as select * from dba_objects; Table created. SQL> update maclean1 set status='INVALID' where owner='MACLEAN'; 2 rows updated. SQL> commit; Commit complete. SQL> create index ind_maclean1 on maclean1(status); Index created. SQL> exec dbms_stats.gather_table_stats('SYS','MACLEAN1',cascade=>true); PL/SQL procedure successfully completed. SQL> explain plan for select * from maclean1 where status='INVALID'; Explained. SQL> set linesize 140 pagesize 1400 SQL> select * from table(dbms_xplan.display()); PLAN_TABLE_OUTPUT --------------------------------------------------------------------------- Plan hash value: 987568083 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 11320 | 1028K| 85 (0)| 00:00:02 | |* 1 | TABLE ACCESS FULL| MACLEAN1 | 11320 | 1028K| 85 (0)| 00:00:02 | ------------------------------------------------------------------------------ Predicate Information (identified by operation id): --------------------------------------------------- 1 - filter("STATUS"='INVALID') 13 rows selected. 10053 trace Access path analysis for MACLEAN1 *************************************** SINGLE TABLE ACCESS PATH   Single Table Cardinality Estimation for MACLEAN1[MACLEAN1]   Column (#10): STATUS(     AvgLen: 7 NDV: 2 Nulls: 0 Density: 0.500000   Table: MACLEAN1  Alias: MACLEAN1     Card: Original: 22639.000000  Rounded: 11320  Computed: 11319.50  Non Adjusted: 11319.50   Access Path: TableScan     Cost:  85.33  Resp: 85.33  Degree: 0       Cost_io: 85.00  Cost_cpu: 11935345       Resp_io: 85.00  Resp_cpu: 11935345   Access Path: index (AllEqRange)     Index: IND_MACLEAN1     resc_io: 185.00  resc_cpu: 8449916     ix_sel: 0.500000  ix_sel_with_filters: 0.500000     Cost: 185.24  Resp: 185.24  Degree: 1   Best:: AccessPath: TableScan          Cost: 85.33  Degree: 1  Resp: 85.33  Card: 11319.50  Bytes: 0 ?????10053????????????,?????Density = 0.5 ?? 1/ NDV ??? ??????????????STATUS='INVALID"???????????, ????????????????? ????”STATUS”=’INVALID’ condition???2?,?status??????,??????dbms_stats?????????????,???CBO????INDEX Range ind_maclean1,???????,??????opitimizer?????? ?????????????????????????,????????,??????????status=’INVALID’???????card??,????????: [oracle@vrh4 ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.2.0 Production on Mon Oct 17 19:15:45 2011 Copyright (c) 1982, 2010, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> select * from v$version; BANNER -------------------------------------------------------------------------------- Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production PL/SQL Release 11.2.0.2.0 - Production CORE 11.2.0.2.0 Production TNS for Linux: Version 11.2.0.2.0 - Production NLSRTL Version 11.2.0.2.0 - Production SQL> show parameter optimizer_fea NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ optimizer_features_enable string 11.2.0.2 SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- www.oracledatabase12g.com & www.askmaclean.com SQL> drop table maclean; Table dropped. SQL> create table maclean as select * from dba_objects; Table created. SQL> update maclean set status='INVALID' where owner='MACLEAN'; 2 rows updated. SQL> commit; Commit complete. SQL> create index ind_maclean on maclean(status); Index created. SQL> exec dbms_stats.gather_table_stats('SYS','MACLEAN',cascade=>true, method_opt=>'FOR ALL COLUMNS SIZE 2'); PL/SQL procedure successfully completed. ???????2?bucket????, ??????????????? ???Quest???Guy Harrison???????FREQUENCY????????,??????: rem rem Generate a histogram of data distribution in a column as recorded rem in dba_tab_histograms rem rem Guy Harrison Jan 2010 : www.guyharrison.net rem rem hexstr function is from From http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:707586567563 set pagesize 10000 set lines 120 set verify off col char_value format a10 heading "Endpoint|value" col bucket_count format 99,999,999 heading "bucket|count" col pct format 999.99 heading "Pct" col pct_of_max format a62 heading "Pct of|Max value" rem col endpoint_value format 9999999999999 heading "endpoint|value" CREATE OR REPLACE FUNCTION hexstr (p_number IN NUMBER) RETURN VARCHAR2 AS l_str LONG := TO_CHAR (p_number, 'fm' || RPAD ('x', 50, 'x')); l_return VARCHAR2 (4000); BEGIN WHILE (l_str IS NOT NULL) LOOP l_return := l_return || CHR (TO_NUMBER (SUBSTR (l_str, 1, 2), 'xx')); l_str := SUBSTR (l_str, 3); END LOOP; RETURN (SUBSTR (l_return, 1, 6)); END; / WITH hist_data AS ( SELECT endpoint_value,endpoint_actual_value, NVL(LAG (endpoint_value) OVER (ORDER BY endpoint_value),' ') prev_value, endpoint_number, endpoint_number, endpoint_number - NVL (LAG (endpoint_number) OVER (ORDER BY endpoint_value), 0) bucket_count FROM dba_tab_histograms JOIN dba_tab_col_statistics USING (owner, table_name,column_name) WHERE owner = '&owner' AND table_name = '&table' AND column_name = '&column' AND histogram='FREQUENCY') SELECT nvl(endpoint_actual_value,endpoint_value) endpoint_value , bucket_count, ROUND(bucket_count*100/SUM(bucket_count) OVER(),2) PCT, RPAD(' ',ROUND(bucket_count*50/MAX(bucket_count) OVER()),'*') pct_of_max FROM hist_data; WITH hist_data AS ( SELECT endpoint_value,endpoint_actual_value, NVL(LAG (endpoint_value) OVER (ORDER BY endpoint_value),' ') prev_value, endpoint_number, endpoint_number, endpoint_number - NVL (LAG (endpoint_number) OVER (ORDER BY endpoint_value), 0) bucket_count FROM dba_tab_histograms JOIN dba_tab_col_statistics USING (owner, table_name,column_name) WHERE owner = '&owner' AND table_name = '&table' AND column_name = '&column' AND histogram='FREQUENCY') SELECT hexstr(endpoint_value) char_value, bucket_count, ROUND(bucket_count*100/SUM(bucket_count) OVER(),2) PCT, RPAD(' ',ROUND(bucket_count*50/MAX(bucket_count) OVER()),'*') pct_of_max FROM hist_data ORDER BY endpoint_value; ?????,??????????FREQUENCY?????: ??dbms_stats ?????STATUS=’INVALID’ bucket count=9 percent = 0.04 ,??????10053 trace????????: SQL> explain plan for select * from maclean where status='INVALID'; Explained. SQL>  select * from table(dbms_xplan.display()); PLAN_TABLE_OUTPUT ------------------------------------- Plan hash value: 3087014066 ------------------------------------------------------------------------------------------- | Id  | Operation                   | Name        | Rows  | Bytes | Cost (%CPU)| Time     | ------------------------------------------------------------------------------------------- |   0 | SELECT STATEMENT            |             |     9 |   837 |     2   (0)| 00:00:01 | |   1 |  TABLE ACCESS BY INDEX ROWID| MACLEAN     |     9 |   837 |     2   (0)| 00:00:01 | |*  2 |   INDEX RANGE SCAN          | IND_MACLEAN |     9 |       |     1   (0)| 00:00:01 | ------------------------------------------------------------------------------------------- Predicate Information (identified by operation id): ---------------------------------------------------    2 - access("STATUS"='INVALID') ??????????????CBO???????STATUS=’INVALID’?cardnality?? , ??????????? ,??index range scan??Full table scan? ????????????????10053 trace: SQL> alter system flush shared_pool; System altered. SQL> oradebug setmypid; Statement processed. SQL> oradebug event 10053 trace name context forever ,level 1; Statement processed. SQL> explain plan for select * from maclean where status='INVALID'; Explained. SINGLE TABLE ACCESS PATH Single Table Cardinality Estimation for MACLEAN[MACLEAN] Column (#10): NewDensity:0.000199, OldDensity:0.000022 BktCnt:22640, PopBktCnt:22640, PopValCnt:2, NDV:2 ???NewDensity= bucket_count / SUM(bucket_count) /2 Column (#10): STATUS( AvgLen: 7 NDV: 2 Nulls: 0 Density: 0.000199 Histogram: Freq #Bkts: 2 UncompBkts: 22640 EndPtVals: 2 Table: MACLEAN Alias: MACLEAN Card: Original: 22640.000000 Rounded: 9 Computed: 9.00 Non Adjusted: 9.00 Access Path: TableScan Cost: 85.30 Resp: 85.30 Degree: 0 Cost_io: 85.00 Cost_cpu: 10804625 Resp_io: 85.00 Resp_cpu: 10804625 Access Path: index (AllEqRange) Index: IND_MACLEAN resc_io: 2.00 resc_cpu: 20763 ix_sel: 0.000398 ix_sel_with_filters: 0.000398 Cost: 2.00 Resp: 2.00 Degree: 1 Best:: AccessPath: IndexRange Index: IND_MACLEAN Cost: 2.00 Degree: 1 Resp: 2.00 Card: 9.00 Bytes: 0 ???????????2 bucket?????CBO????????????,???????????????????,???dbms_stats.DEFAULT_METHOD_OPT????????????????????? ???dbms_stats?????????????????????col_usage$??????predicate???????,??col_usage$??<????????SMON??(?):??col_usage$????>? ??????????dbms_stats????????,col_usage$????????????predicate???,??dbms_stats??????????????????, ?: SQL> drop table maclean; Table dropped. SQL> create table maclean as select * from dba_objects; Table created. SQL> update maclean set status='INVALID' where owner='MACLEAN'; 2 rows updated. SQL> commit; Commit complete. SQL> create index ind_maclean on maclean(status); Index created. ??dbms_stats??method_opt??maclean? SQL> exec dbms_stats.gather_table_stats('SYS','MACLEAN'); PL/SQL procedure successfully completed. @histogram.sql Enter value for owner: SYS old  12:    WHERE owner = '&owner' new  12:    WHERE owner = 'SYS' Enter value for table: MACLEAN old  13:      AND table_name = '&table' new  13:      AND table_name = 'MACLEAN' Enter value for column: STATUS old  14:      AND column_name = '&column' new  14:      AND column_name = 'STATUS' no rows selected ????col_usage$?????,????????status????? declare begin for i in 1..500 loop execute immediate ' alter system flush shared_pool'; DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO; execute immediate 'select count(*) from maclean where status=''INVALID'' ' ; end loop; end; / PL/SQL procedure successfully completed. SQL> select obj# from obj$ where name='MACLEAN';       OBJ# ----------      97215 SQL> select * from  col_usage$ where  OBJ#=97215;       OBJ#    INTCOL# EQUALITY_PREDS EQUIJOIN_PREDS NONEQUIJOIN_PREDS RANGE_PREDS LIKE_PREDS NULL_PREDS TIMESTAMP ---------- ---------- -------------- -------------- ----------------- ----------- ---------- ---------- ---------      97215          1              1              0                 0           0          0          0 17-OCT-11      97215         10            499              0                 0           0          0          0 17-OCT-11 SQL> exec dbms_stats.gather_table_stats('SYS','MACLEAN'); PL/SQL procedure successfully completed. @histogram.sql Enter value for owner: SYS Enter value for table: MACLEAN Enter value for column: STATUS Endpoint        bucket         Pct of value            count     Pct Max value ---------- ----------- ------- -------------------------------------------------------------- INVALI               2     .04 VALIC3           5,453   99.96  *************************************************

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• IIS 7, Asp.Net 4: Server cannot append header after HTTP headers have been sent?

  - by Amitabh

  I am getting the following warnings on the Event Log for a Asp.Net WebSite running on IIS 7. Exception information: Exception type: HttpException Exception message: Server cannot append header after HTTP headers have been sent. at System.Web.Hosting.ISAPIWorkerRequest.SendUnknownResponseHeader(String name, String value) at System.Web.HttpResponse.WriteHeaders() at System.Web.HttpResponse.Flush(Boolean finalFlush) at System.Web.HttpRuntime.FinishRequest(HttpWorkerRequest wr, HttpContext context, Exception e) I tried to debug the WebSite but it just does not show in debugger. The web page which has got this issue contains the following. Its a content page with a Master page. It has a grid inside an UpdatePanel which is Triggered by a Timer. On the specified time grid data is refreshed. Everytime this happens we see a new warning in the EventLog. What is the best way to go about this issue?

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• Persistence provider caller does not implement the EJB3 spec

  - by Joshua

  WARN [Ejb3Configuration] Persistence provider caller does not implement the EJB3 spec correctly. PersistenceUnitInfo.getNewTempClassLoad er() is null. How do you get rid of the above warning? 0:42:08,032 INFO [PersistenceUnitDeployment] Starting persistence unit pe rsistence.unit:unitName=k12-ear.ear/k12-ejb-1.0.0.jar#k12 10:42:08,371 INFO [Version] Hibernate Annotations 3.4.0.GA 10:42:08,442 INFO [Environment] Hibernate 3.3.1.GA 10:42:08,450 INFO [Environment] hibernate.properties not found 10:42:08,486 INFO [Environment] Bytecode provider name : javassist 10:42:08,492 INFO [Environment] using JDK 1.4 java.sql.Timestamp handling 10:42:08,754 INFO [Version] Hibernate Commons Annotations 3.1.0.GA 10:42:08,989 INFO [Version] Hibernate EntityManager 3.4.0.GA 10:42:09,211 INFO [Ejb3Configuration] Processing PersistenceUnitInfo [ name: k12 ...] 10:42:09,458 WARN [Ejb3Configuration] Persistence provider caller does not implement the EJB3 spec correctly. PersistenceUnitInfo.getNewTempClassLoad er() is null. 10:42:09,620 WARN [Ejb3Configuration] Defining hibernate.transaction.flush _before_completion=true ignored in HEM 10:42:09,745 DEBUG [AnnotationConfiguration] Execute first pass mapping pro cessing

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• using grails and google app engine to store image as blob and the view dynamically

  - by mswallace

  I am trying to dynamically display an image that I am storing in the google datastore as a Blob. I am not getting any errors but I am getting a broken image on the page that I view. Any help would be awesome! I have the following code in my grails app domain class has the following @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) Long id @Persistent String siteName @Persistent String url @Persistent Blob img @Persistent String yourName @Persistent String yourURL @Persistent Date date static constraints = { id( visible:false) } My save method in the controller has this def save = { params.img = new Blob(params.imgfile.getBytes()) def siteInfoInstance = new SiteInfo(params) if(!siteInfoInstance.hasErrors() ) { try{ persistenceManager.makePersistent(siteInfoInstance) } finally{ flash.message = "SiteInfo ${siteInfoInstance.id} created" redirect(action:show,id:siteInfoInstance.id) } } render(view:'create',model:[siteInfoInstance:siteInfoInstance]) } My view has the following <img src="${createLink(controller:'siteInfoController', action:'showImage', id:fieldValue(bean:siteInfoInstance, field:'id'))}"></img> and the method in my controller that it is calling to display a link to the image looks like this def showImage = { def site = SiteInfo.get(params.id)// get the record response.outputStream << site.img // write the image to the outputstream response.outputStream.flush() }

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• WCF CreateMessage from custom body xml

  - by Cecil

  I have the following code: string body = "<custom xml>"; XDocument doc = XDocument.Parse(body); MemoryStream stream = new MemoryStream(); XmlWriter writer = XmlWriter.Create(stream); if (writer != null) { doc.Save(writer); writer.Flush(); writer.Close(); } stream.Position = 0; XmlReader rd = XmlReader.Create(stream); Message output = Message.CreateMessage(msg.Version, msg.Headers.Action, rd); output.Headers.CopyHeadersFrom(msg); output.Properties.CopyProperties(msg.Properties); When I try to use the message I get the following error: hexadecimal value 0x02, is an invalid character. Line 1, position 2. Any idea why? And what I can do to fix this?

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• Downloading file from server (asp.net) to IE8 Content-Disposition problem with file name

  - by David

  I am downloading a file from the server/database via aspx page. When using the content-disposition inline the document opens in correct application but the file name is the same as the web page. I want the document to open in say MS Word but with the correct file name. Here is the code that I am using Response.Buffer = true; Response.ClearContent(); Response.ClearHeaders(); Response.Clear(); Response.ContentType = MimeType(fileName); //function to return the correct MIME TYPE Response.AddHeader("Content-Disposition", @"inline;filename=" + fileName); Response.AddHeader("Content-Length", image.Length.ToString()); Response.BinaryWrite(image); Response.Flush(); Response.Close(); So again, I want the file to open in MS Word with the correct document file name so that the user can properly save/view. Ideas? thanks

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• IIS7 Integrated Pipeline - Response.End not ending the request.

  - by MikeGurtzweiler

  I have the following bit of code that worked as expected before we upgraded to Integrated Pipeline in IIS7. public void RedirectPermanently(string url, bool clearCookies) { Response.ClearContent(); Response.StatusCode = 301; Response.AppendHeader("Location", url); if(clearCookies) { Response.Cookies.Clear(); Response.Flush(); Response.End(); } } Previously when this method was executed, if clearCookies was true, the response would be sent to the client and request processing would end. Now under Integrated Pipeline Response.End() does not seem to end processing. The page continues running as if the method was never called. Big question is, why and what changed! Thanks.

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• How do I use Google protobuf to communicate over a serial port?

  - by rob

  I'm working on a project that uses RXTX and protobuf to communicate with an application on a development board and I've been running into issues which implies that I'm likely doing things the wrong way. Here's what I currently have for writing the request to the board (the read code is similar): public void write(CableCommandRequest request, OutputStream out) { CodedOutputStream outStream = CodedOutputStream.newInstance(out); request.writeTo(outStreatm); outStream.flush(); } The OutputStream that is used is prepared by RXTX and the development board seems to indicate that data is being received, but it is getting garbled or is otherwise not being understood. There seems to be little documentation on using protobuf over a serial connection so I'm assuming that passing the OutputStream should be sufficient. Is this in fact correct, or is this the wrong way of sending the response over the serial connection?

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• Eventlet client-server

  - by johannix

  I'm trying to setup a server-client interraction: Server gets a string from client Server returns data to client I got this working with socket.send and socket.recv, but was wondering how to get it working with files through socket.makefile. I've got most of the pieces working, but don't know how to force each of the pieces to read at the appropriate time. So what it looks like is happening is that both the client and server are reading on the socket at the same time. Any ideas on how to let the server complete the original read before the client starts waiting for its information? Below are the core pieces that reproduce the read lock. Server: def handle(green_socket): file_handler = green_socket.makefile('rw') print 'before server read' lines = file_handler.readlines() print "readlines: %s" % (lines) print '** Server started **' server = eventlet.listen((HOST, PORT)) pool = eventlet.GreenPool() while True: new_sock, address = server.accept() pool.spawn_n(handle, new_sock) Client: from eventlet.green import socket green_socket = eventlet.connect((HOST, PORT)) file_handler = green_socket.makefile('rw') print 'before write' file_handler.writelines('client message') file_handler.flush() print 'before client read' lines = file_handler.readlines()

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• FileStream to save file then immediately unlock in C# ?

  - by aron

  Hello, I have this code that saves a pdf file. FileStream fs = new FileStream(SaveLocation, FileMode.Create); fs.Write(result.DocumentBytes, 0, result.DocumentBytes.Length); fs.Flush(); fs.Close(); It works fine. However sometimes it does not release the lock right away and that causes file locking exceptions with functions run after this one run. Is there a ideal way to release the file lock right after the fs.Close() thanks!

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• XMPP TLS connection with SslStream

  - by Marcom

  I am trying to create a simple xmpp client that connects to Gtalk. The first part of the handshake seems to work. Ror the TLS handshake I created a client SslStream, connected to the intended server (talk.google.com) and successfully got authenticated . The first SSlStream.Read is to receive the greeting reply, it went fine . I do a SslStream.write to send my first command, but when i do my Sslstream.Read() to get the reply , i get this error."System.IO.IOException: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine." Can anyone point me to the right direction? I am using code very similar to the example on msdn http://msdn.microsoft.com/en-us/library/system.net.security.sslstream.aspx except that I switch from a Network stream to a Sslstream when TLS is negotiated. netStream.Flush(); sslStream = new SslStream(netStream, true, new RemoteCertificateValidationCallback(ValidateServerCertificate), null ); sslStream.AuthenticateAsClient("talk.google.com");

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• JPA 2.0 EclipseLink Check for unique

  - by Parhs

  Hello... I have a collumn as unique=true.. in Exam class.... I found that because transactions are commited automaticaly so to force the commit i use em.commit() However i would like to know how to check if it is unique.Running a query isnt a solution because it may be an instert after checking because of the concurency.... Which is the best way to check for uniqness? List<Exam_Normal> exam_normals = exam.getExam_Normal(); exam.setExam_Normal(null); try { em.persist(exam); em.flush(); Long i = 0L; if (exam_normals != null) { for (Exam_Normal e_n : exam_normals) { i++; e_n.setItem(i); e_n.setId(exam); em.persist(e_n); } } } catch (Exception e) { System.out.print("sfalma--"); } } d

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• doubt in JSP:Include

  - by raja

  Hi All: I have added a code which will include child jsp using jsp:include. The problem i am facing is that the code present in child code is not executing. Below is the code iam using it now JSPF File: <jsp:include page="X.jsp" flush="true"> </jsp:include> the above code is present in a file named "A.jspf" which is included in another jsp file named "Parent.jsp". X.jsp: <%@ page import="java.util.*" %> <% System.out.println("********Child JSP"); %> Whenever i execute the parent file "Parent.jsp", all the other contents given in Parent.jsp and A.jspf is displaying except the content present in X.jsp. No error is displaying. Both X.jsp and A.jspf are present in same folder only. Please help me to resolve this issue. Thanks in advance.

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• Caching the xml response from a HttpHandler

  - by Blankman

  My HttpHandler looks like: public void ProcessRequest(HttpContext context) { context.Response.ContentType = "text/xml"; XmlWriter writer = new XmlTextWriter(context.Response.OutputStream, Encoding.UTF8); writer.WriteStartDocument(); writer.WriteStartElement("ProductFeed"); DataTable dt = GetStuff(); for(...) { } writer.WriteEndElement(); writer.WriteEndDocument(); writer.Flush(); writer.Close(); } How can I cache the entire xml document that I am generating? Or do I only have the option of caching the DataTable object?

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• .NET sendkeys to calculator

  - by user203123

  The sendkeys code below works well for Notepad but it doesn't work for Calculator. What is the problem? (It's another problem compared to what I sent here http://stackoverflow.com/questions/2604486/c-sendkeys-problem) [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern IntPtr FindWindow(string lpClassName,string lpWindowName); [DllImport("User32")] public static extern bool SetForegroundWindow(IntPtr hWnd); private void button1_Click(object sender, EventArgs e) { IntPtr calculatorHandle = FindWindow("SciCalc", "Calculator"); //IntPtr calculatorHandle = FindWindow("Notepad", "Untitled - Notepad"); if (calculatorHandle == IntPtr.Zero) { MessageBox.Show("Calculator is not running."); return; } SetForegroundWindow(calculatorHandle); System.Threading.Thread.Sleep(1000); SendKeys.SendWait("111*11="); //SendKeys.SendWait("{ENTER}"); //cnt++; SendKeys.Flush(); }

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• Use a "x-dom-event-stream" stream in javascript ?

  - by rnaud

  Hello, HTML5 draft contains an API called EventSource to stream data (notifications) trough javascript using only one server call. Looking it up, I found an exemple on Opera Labs of the javascript part : document.getElementsByTagName("event-source")[0] .addEventListener("server-time", eventHandler, false); function eventHandler(event) { // Alert time sent by the server alert(event.data); } and the server side part : <?php header("Content-Type: application/x-dom-event-stream"); while(true) { echo "Event: server-time\n"; $time = time(); echo "data: $time\n"; echo "\n"; flush(); sleep(3); } ?> But as of today, it seems only Opera has implemented the API, neither Chrome nor Safari have a working version (Am I wrong here ?) So my question is, is there any other way in javascript, maybe more complex, to use this one stream to get data ?

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• Problem using Hibernate-Search

  - by KCore

  Hi, I am using hibernate search for my application. It is well configured and running perfectly till some time back, when it stopped working suddenly. The reason according to me being the number of my model (bean) classes. I have some 90 classes, which I add to my configuration, while building my Hibernate Configuration. When, I disable hibernate search (remove the search annotations and use Configuration instead of AnnotationsConfiguration), I try to start my application, it Works fine. But,the same app when I enable search, it just hangs up. I tried debugging and found the exact place where it hangs. After adding all the class to my AnnotationsConfiguration object, when I say cfg.buildSessionfactory(), It never comes out of that statement. (I have waited for hours!!!) Also when I decrease the number of my model classes (like say to half i.e. 50) it comes out of that statement and the application works fine.. Can Someone tell why is this happening?? My versions of hibernate are: hibernate-core-3.3.1.GA.jar hibernate-annotations-3.4.0.GA.jar hibernate-commons-annotations-3.1.0.GA.jar hibernate-search-3.1.0.GA.jar Also if need to avoid using AnnotationsConfiguration, I read that I need to configure the search event listeners explicitly.. can anyone list all the neccessary listeners and their respective classes? (I tried the standard ones given in Hibernate Search books, but they give me ClassNotFound exception and I have all the neccesarty libs in classpath) Here are the last few lines of hibernate trace I managed to pull : 16:09:32,814 INFO AnnotationConfiguration:369 - Hibernate Validator not found: ignoring 16:09:32,892 INFO ConnectionProviderFactory:95 - Initializing connection provider: org.hibernate.connection.C3P0ConnectionProvider 16:09:32,895 INFO C3P0ConnectionProvider:103 - C3P0 using driver: com.mysql.jdbc.Driver at URL: jdbc:mysql://localhost:3306/autolinkcrmcom_data 16:09:32,898 INFO C3P0ConnectionProvider:104 - Connection properties: {user=root, password=****} 16:09:32,900 INFO C3P0ConnectionProvider:107 - autocommit mode: false 16:09:33,694 INFO SettingsFactory:116 - RDBMS: MySQL, version: 5.1.37-1ubuntu5.1 16:09:33,696 INFO SettingsFactory:117 - JDBC driver: MySQL-AB JDBC Driver, version: mysql-connector-java-3.1.10 ( $Date: 2005/05/19 15:52:23 $, $Revision: 1.1.2.2 $ ) 16:09:33,701 INFO Dialect:175 - Using dialect: org.hibernate.dialect.MySQLDialect 16:09:33,707 INFO TransactionFactoryFactory:59 - Using default transaction strategy (direct JDBC transactions) 16:09:33,709 INFO TransactionManagerLookupFactory:80 - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) 16:09:33,711 INFO SettingsFactory:170 - Automatic flush during beforeCompletion(): disabled 16:09:33,714 INFO SettingsFactory:174 - Automatic session close at end of transaction: disabled 16:09:32,814 INFO AnnotationConfiguration:369 - Hibernate Validator not found: ignoring 16:09:32,892 INFO ConnectionProviderFactory:95 - Initializing connection provider: org.hibernate.connection.C3P0ConnectionProvider 16:09:32,895 INFO C3P0ConnectionProvider:103 - C3P0 using driver: com.mysql.jdbc.Driver at URL: jdbc:mysql://localhost:3306/autolinkcrmcom_data 16:09:32,898 INFO C3P0ConnectionProvider:104 - Connection properties: {user=root, password=****} 16:09:32,900 INFO C3P0ConnectionProvider:107 - autocommit mode: false 16:09:33,694 INFO SettingsFactory:116 - RDBMS: MySQL, version: 5.1.37-1ubuntu5.1 16:09:33,696 INFO SettingsFactory:117 - JDBC driver: MySQL-AB JDBC Driver, version: mysql-connector-java-3.1.10 ( $Date: 2005/05/19 15:52:23 $, $Revision: 1.1.2.2 $ ) 16:09:33,701 INFO Dialect:175 - Using dialect: org.hibernate.dialect.MySQLDialect 16:09:33,707 INFO TransactionFactoryFactory:59 - Using default transaction strategy (direct JDBC transactions) 16:09:33,709 INFO TransactionManagerLookupFactory:80 - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended) 16:09:33,711 INFO SettingsFactory:170 - Automatic flush during beforeCompletion(): disabled 16:09:33,714 INFO SettingsFactory:174 - Automatic session close at end of transaction: disabled 16:09:33,716 INFO SettingsFactory:181 - JDBC batch size: 15 16:09:33,719 INFO SettingsFactory:184 - JDBC batch updates for versioned data: disabled 16:09:33,721 INFO SettingsFactory:189 - Scrollable result sets: enabled 16:09:33,723 DEBUG SettingsFactory:193 - Wrap result sets: disabled 16:09:33,725 INFO SettingsFactory:197 - JDBC3 getGeneratedKeys(): enabled 16:09:33,727 INFO SettingsFactory:205 - Connection release mode: auto 16:09:33,730 INFO SettingsFactory:229 - Maximum outer join fetch depth: 2 16:09:33,732 INFO SettingsFactory:232 - Default batch fetch size: 1000 16:09:33,735 INFO SettingsFactory:236 - Generate SQL with comments: disabled 16:09:33,737 INFO SettingsFactory:240 - Order SQL updates by primary key: disabled 16:09:33,740 INFO SettingsFactory:244 - Order SQL inserts for batching: disabled 16:09:33,742 INFO SettingsFactory:420 - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory 16:09:33,744 INFO ASTQueryTranslatorFactory:47 - Using ASTQueryTranslatorFactory 16:09:33,747 INFO SettingsFactory:252 - Query language substitutions: {} 16:09:33,750 INFO SettingsFactory:257 - JPA-QL strict compliance: disabled 16:09:33,752 INFO SettingsFactory:262 - Second-level cache: enabled 16:09:33,754 INFO SettingsFactory:266 - Query cache: disabled 16:09:33,757 INFO SettingsFactory:405 - Cache region factory : org.hibernate.cache.impl.bridge.RegionFactoryCacheProviderBridge 16:09:33,759 INFO RegionFactoryCacheProviderBridge:61 - Cache provider: net.sf.ehcache.hibernate.EhCacheProvider 16:09:33,762 INFO SettingsFactory:276 - Optimize cache for minimal puts: disabled 16:09:33,764 INFO SettingsFactory:285 - Structured second-level cache entries: disabled 16:09:33,766 INFO SettingsFactory:314 - Statistics: disabled 16:09:33,769 INFO SettingsFactory:318 - Deleted entity synthetic identifier rollback: disabled 16:09:33,771 INFO SettingsFactory:333 - Default entity-mode: pojo 16:09:33,774 INFO SettingsFactory:337 - Named query checking : enabled 16:09:33,869 INFO Version:20 - Hibernate Search 3.1.0.GA 16:09:35,134 DEBUG DocumentBuilderIndexedEntity:157 - Field selection in projections is set to false for entity **com.xyz.abc**. recognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernaterecognized hibernateDocumentBuilderIndexedEntity Donno what the last line indicates ??? (hibernaterecognized....) After the last line it doesnt do anything (no trace too ) and just hangs....

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• C# sendkeys to calculator

  - by user203123

  The sendkeys code below works well for Notepad but it doesn't work for Calculator. What is the problem? (It's another problem compared to what I sent here http://stackoverflow.com/questions/2604486/c-sendkeys-problem) [DllImport("user32.dll", CharSet = CharSet.Unicode)] public static extern IntPtr FindWindow(string lpClassName,string lpWindowName); [DllImport("User32")] public static extern bool SetForegroundWindow(IntPtr hWnd); private void button1_Click(object sender, EventArgs e) { IntPtr calculatorHandle = FindWindow("SciCalc", "Calculator"); //IntPtr calculatorHandle = FindWindow("Notepad", "Untitled - Notepad"); if (calculatorHandle == IntPtr.Zero) { MessageBox.Show("Calculator is not running."); return; } SetForegroundWindow(calculatorHandle); System.Threading.Thread.Sleep(1000); SendKeys.SendWait("111*11="); //SendKeys.SendWait("{ENTER}"); //cnt++; SendKeys.Flush(); }

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• C# WebClient only downloads partial html

  - by H4mm3rHead

  Hi, I am working on some scraping app, i wanted to try to get it to work but ran into a problem. I have replaced the original scraping destination in the below code with googles webpage, just for testing. It seems that my download doesnt get everything, i note that the body and the html tags are missing their close tags. How do i get it to download everything? Whats wrong with my sample code: string filename = "test.html"; WebClient client = new WebClient(); string searchTerm = HttpUtility.UrlEncode(textBox2.Text); client.QueryString.Add("q", searchTerm); client.QueryString.Add("hl", "en"); string data = client.DownloadString("http://www.google.com/search"); StreamWriter writer = new StreamWriter(filename, false, Encoding.Unicode); writer.Write(data); writer.Flush(); writer.Close();

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• SpeechSynthesizer in C# creates wav that has 22kHz... needs to be 16kHz

  - by Adrian

  My C# application needs to covert text to wav file and inject it into a Skype call. The code that creates the wav file is below. The problem is that the file has 22kHz sample rate and Skype accepts only 16kHz. Is there any way to adjust this setting? using (System.IO.FileStream stream = System.IO.File.Create("message.wav")) { System.Speech.Synthesis.SpeechSynthesizer speechEngine = new System.Speech.Synthesis.SpeechSynthesizer(); speechEngine.SetOutputToWaveStream(stream); speechEngine.Speak(number); stream.Flush(); }

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• ASM programming, how to use loop?

  - by chris

  Hello. Im first time here.I am a college student. I've created a simple program by using assembly language. And im wondering if i can use loop method to run it almost samething as what it does below the program i posted. and im also eager to find someome who i can talk through MSN messanger so i can ask you questions right away.(if possible) ok thank you .MODEL small .STACK 400h .data prompt db 10,13,'Please enter a 3 digit number, example 100:',10,13,'$' ;10,13 cause to go to next line first_digit db 0d second_digit db 0d third_digit db 0d Not_prime db 10,13,'This number is not prime!',10,13,'$' prime db 10,13,'This number is prime!',10,13,'$' question db 10,13,'Do you want to contine Y/N $' counter dw 0d number dw 0d half dw ? .code Start: mov ax, @data ;establish access to the data segment mov ds, ax mov number, 0d LetsRoll: mov dx, offset prompt ; print the string (please enter a 3 digit...) mov ah, 9h int 21h ;execute ;read FIRST DIGIT mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov first_digit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, doubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 100d ;This is so we can calculate 100*1st digit +10*2nd digit + 3rd digit mul cx ;start to accumulate the 3 digit number in the variable imul cx ;it is understood that the other operand is ax ;AND that the result will use both dx::ax ;but we understand that dx will contain only leading zeros add number, ax ;save ;variable <number> now contains 1st digit * 10 ;---------------------------------------------------------------------- ;read SECOND DIGIT, multiply by 10 and add in mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov second_digit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, boubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer mov cx, 10d ;continue to accumulate the 3 digit number in the variable mul cx ;it is understood that the other operand is ax, containing first digit ;AND that the result will use both dx::ax ;but we understand that dx will contain only leading zeros. Ignore them add number, ax ;save -- nearly finished ;variable <number> now contains 1st digit * 100 + second digit * 10 ;---------------------------------------------------------------------- ;read THIRD DIGIT, add it in (no multiplication this time) mov ah, 1d ;bios code for read a keystroke int 21h ;call bios, it is understood that the ascii code will be returned in al mov third_digit, al ;may as well save a copy sub al, 30h ;Convert code to an actual integer cbw ;CONVERT BYTE TO WORD. This takes whatever number is in al and ;extends it to ax, boubling its size from 8 bits to 16 bits ;The first digit now occupies all of ax as an integer add number, ax ;Both my variable number and ax are 16 bits, so equal size mov ax, number ;copy contents of number to ax mov cx, 2h div cx ;Divide by cx mov half, ax ;copy the contents of ax to half mov cx, 2h; mov ax, number; ;copy numbers to ax xor dx, dx ;flush dx jmp prime_check ;jump to prime check print_question: mov dx, offset question ;print string (do you want to continue Y/N?) mov ah, 9h int 21h ;execute mov ah, 1h int 21h ;execute cmp al, 4eh ;compare je Exit ;jump to exit cmp al, 6eh ;compare je Exit ;jump to exit cmp al, 59h ;compare je Start ;jump to start cmp al, 79h ;compare je Start ;jump to start prime_check: div cx; ;Divide by cx cmp dx, 0h ;reset the value of dx je print_not_prime ;jump to not prime xor dx, dx; ;flush dx mov ax, number ;copy the contents of number to ax cmp cx, half ;compare half with cx je print_prime ;jump to print prime section inc cx; ;increment cx by one jmp prime_check ;repeat the prime check print_prime: mov dx, offset prime ;print string (this number is prime!) mov ah, 9h int 21h ;execute jmp print_question ;jumps to question (do you want to continue Y/N?) this is for repeat print_not_prime: mov dx, offset Not_prime ;print string (this number is not prime!) mov ah, 9h int 21h ;execute jmp print_question ;jumps to question (do you want to continue Y/N?) this is for repeat Exit: mov ah, 4ch int 21h ;execute exit END Start

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• Sending multipart response for downloads in Zend Framework

  - by takeshin

  I'm sending files in action helper for downloads (in parts if needed) like this: ... $response->sendHeaders(); $chunksize = 1 * (1024 * 1024); $bytesSent = 0; if ($httpRange) { fseek($file, $range); } while(!feof($file) && (!connection_aborted() && ($bytesSent < $newLength)) ) { $buffer = fread($file, $chunksize); // $response->appendBody($buffer); // this would be better print($buffer); flush(); $bytesSent += strlen($buffer); } fclose($file); I suspect that better way would be to make use of $response object instead of print. Which is the recommended way to send big response objects using Zend Framework?

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