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• Why It Is So Important to Know Your Customer

  - by Christie Flanagan

  Over the years, I endured enough delayed flights, air turbulence and misadventures in airport security clearance to watch my expectations for the air travel experience fall to abysmally low levels. The extent of my loyalty to any one carrier had more to do with the proximity of the airport parking garage to their particular gate than to any effort on the airline’s part to actually earn and retain my business. That all changed one day when I found myself at the airport hoping to catch a return flight home a few hours earlier than expected, using an airline I had flown with for the first time just that week.  When you travel regularly for business, being able to catch a return flight home that’s even an hour or two earlier than originally scheduled is a big deal. It can mean the difference between having a normal evening with your family and having to sneak in like a cat burglar after everyone is fast asleep. And so I found myself on this particular day hoping to catch an earlier flight home. I approached the gate agent and was told that I could go on standby for their next flight out. Then I asked how much it was going to cost to change the flight, knowing full well that I wouldn’t get reimbursed by my company for any change fees. “Oh, there’s no charge to fly on standby,” the gate agent told me. I made a funny look. I couldn’t believe what I was hearing. This airline was going to let my fly on standby, at no additional charge, even though I was a new customer with no status or points. It had been years since I’d seen an airline pass up a short term revenue generating opportunity in favor of a long term loyalty generating one.  At that moment, this particular airline gained my loyal business. Since then, this airline has had the opportunity to learn a lot about me. They know where I live, where I fly from, where I usually fly to, and where I like to sit on the plane. In general, I’ve found their customer service to be quite good whether at the airport, via call center and even through social channels. They email me occasionally, and when they do, they demonstrate that they know me by promoting deals for flights from where I live to places that I’d be interested in visiting. And that’s part of why I’m always so puzzled when I visit their website.Does this company with the great service, customer friendly policies, and clean planes demonstrate that they know me at all when I visit their website? The answer is no. Even when I log in using my loyalty program credentials, it’s pretty obvious that they’re presenting the same old home page and same old offers to every single one of their site visitors. I mean, those promotional offers that they’re featuring so prominently  -- they’re for flights that originate thousands of miles from where I live! There’s no way I’d ever book one of those flights and I’m sure I’m not the only one of their customers to feel that way.My reason for recounting this story is not to pick on the one customer experience flaw I've noticed with this particular airline, in fact, they do so many things right that I’ll continue to fly with them. But I did want to illustrate just how glaringly obvious it is to customers today when a touch point they have with a brand is impersonal, unconnected and out of sync. As someone who’s spent a number of years in the web experience management and online marketing space, it particularly peeves me when that out of sync touch point is a brand’s website, perhaps because I know how important it is to make a customer’s online experience relevant and how many powerful tools are available for making a relevant experience a reality. The fact is, delivering a one-size-fits-all online customer experience is no longer acceptable or particularly effective in today’s world. Today’s savvy customers expect you to know who they are and to understand their preferences, behavior and relationship with your brand. Not only do they expect you to know about them, but they also expect you to demonstrate this knowledge across all of their touch points with your brand in a consistent and compelling fashion, whether it be on your traditional website, your mobile web presence or through various social channels.Delivering the kind of personalized online experiences that customers want can have tremendous business benefits. This is not just about generating feelings of goodwill and higher customer satisfaction ratings either. More relevant and personalized online experiences boost the effectiveness of online marketing initiatives and the statistics prove this out. Personalized web experiences can help increase online conversion rates by 70% -- that’s a huge number.1  And more than three quarters of consumers indicate that they’ve made additional online purchases based on personalized product recommendations.2Now if only this airline would get on board with delivering a more personalized online customer experience. I’d certainly be happier and more likely to spring for one of their promotional offers. And by targeting relevant offers on their home page to appropriate segments of their site visitors, I bet they’d be happier and generating additional revenue too. Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* 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:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}  ***** If you're interested in hearing more perspectives on the benefits of demonstrating that you know your customers by delivering a more personalized experience, check out this white paper on creating a successful and meaningful customer experience on the web.  Also catch the video below on the business value of CX in attracting new customers featuring Oracle's VP of Customer Experience Strategy, Brian Curran. 1 Search Engine Watch 2 Marketing Charts

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• How to archive data from a table to a local or remote database in SQL 2005 and SQL 2008

  - by simonsabin

  Often you have the need to archive data from a table. This leads to a number of challenges 1. How can you do it without impacting users 2. How can I make it transactionally consistent, i.e. the data I put in the archive is the data I remove from the main table 3. How can I get it to perform well Points 1 is very much tied to point 3. If it doesn't perform well then the delete of data is going to cause lots of locks and thus potentially blocking. For points 1 and 3 refer to my previous posts DELETE-TOP-x-rows-avoiding-a-table-scan and UPDATE-and-DELETE-TOP-and-ORDER-BY---Part2. In essence you need to be removing small chunks of data from your table and you want to do that avoiding a table scan. So that deals with the delete approach but archiving is about inserting that data somewhere else. Well in SQL 2008 they introduced a new feature INSERT over DML (Data Manipulation Language, i.e. SQL statements that change data), or composable DML. The ability to nest DML statements within themselves, so you can past the results of an insert to an update to a merge. I've mentioned this before here SQL-Server-2008---MERGE-and-optimistic-concurrency. This feature is currently limited to being able to consume the results of a DML statement in an INSERT statement. There are many restrictions which you can find here http://msdn.microsoft.com/en-us/library/ms177564.aspx look for the section "Inserting Data Returned From an OUTPUT Clause Into a Table" Even with the restrictions what we can do is consume the OUTPUT from a DELETE and INSERT the results into a table in another database. Note that in BOL it refers to not being able to use a remote table, remote means a table on another SQL instance. To show this working use this SQL to setup two databases foo and fooArchive create database foo go --create the source table fred in database foo select * into foo..fred from sys.objects go create database fooArchive go if object_id('fredarchive',DB_ID('fooArchive')) is null begin     select getdate() ArchiveDate,* into fooArchive..FredArchive from sys.objects where 1=2       end go And then we can use this simple statement to archive the data insert into fooArchive..FredArchive select getdate(),d.* from (delete top (1)         from foo..Fred         output deleted.*) d         go In this statement the delete can be any delete statement you wish so if you are deleting by ids or a range of values then you can do that. Refer to the DELETE-TOP-x-rows-avoiding-a-table-scan post to ensure that your delete is going to perform. The last thing you want to do is to perform 100 deletes each with 5000 records for each of those deletes to do a table scan. For a solution that works for SQL2005 or if you want to archive to a different server then you can use linked servers or SSIS. This example shows how to do it with linked servers. [ONARC-LAP03] is the source server. begin transaction insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*') d commit transaction and to prove the transactions work try, you should get the same number of records before and after. select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive   begin transaction insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*') d rollback transaction   select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive The transactions are very important with this solution. Look what happens when you don't have transactions and an error occurs   select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive   insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*                     raiserror (''Oh doo doo'',15,15)') d                     select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive Before running this think what the result would be. I got it wrong. What seems to happen is that the remote query is executed as a transaction, the error causes that to rollback. However the results have already been sent to the client and so get inserted into the

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• PostSharp, Obfuscation, and IL

  - by Simon Cooper

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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• ASP.NET WebAPI Security 3: Extensible Authentication Framework

  - by Your DisplayName here!

  In my last post, I described the identity architecture of ASP.NET Web API. The short version was, that Web API (beta 1) does not really have an authentication system on its own, but inherits the client security context from its host. This is fine in many situations (e.g. AJAX style callbacks with an already established logon session). But there are many cases where you don’t use the containing web application for authentication, but need to do it yourself. Examples of that would be token based authentication and clients that don’t run in the context of the web application (e.g. desktop clients / mobile). Since Web API provides a nice extensibility model, it is easy to implement whatever security framework you want on top of it. My design goals were: Easy to use. Extensible. Claims-based. ..and of course, this should always behave the same, regardless of the hosting environment. In the rest of the post I am outlining some of the bits and pieces, So you know what you are dealing with, in case you want to try the code. At the very heart… is a so called message handler. This is a Web API extensibility point that gets to see (and modify if needed) all incoming and outgoing requests. Handlers run after the conversion from host to Web API, which means that handler code deals with HttpRequestMessage and HttpResponseMessage. See Pedro’s post for more information on the processing pipeline. This handler requires a configuration object for initialization. Currently this is very simple, it contains: Settings for the various authentication and credential types Settings for claims transformation Ability to block identity inheritance from host The most important part here is the credential type support, but I will come back to that later. The logic of the message handler is simple: Look at the incoming request. If the request contains an authorization header, try to authenticate the client. If this is successful, create a claims principal and populate the usual places. If not, return a 401 status code and set the Www-Authenticate header. Look at outgoing response, if the status code is 401, set the Www-Authenticate header. Credential type support Under the covers I use the WIF security token handler infrastructure to validate credentials and to turn security tokens into claims. The idea is simple: an authorization header consists of two pieces: the schema and the actual “token”. My configuration object allows to associate a security token handler with a scheme. This way you only need to implement support for a specific credential type, and map that to the incoming scheme value. The current version supports HTTP Basic Authentication as well as SAML and SWT tokens. (I needed to do some surgery on the standard security token handlers, since WIF does not directly support string-ified tokens. The next version of .NET will fix that, and the code should become simpler then). You can e.g. use this code to hook up a username/password handler to the Basic scheme (the default scheme name for Basic Authentication). config.Handler.AddBasicAuthenticationHandler( (username, password) => username == password); You simply have to provide a password validation function which could of course point back to your existing password library or e.g. membership. The following code maps a token handler for Simple Web Tokens (SWT) to the Bearer scheme (the currently favoured scheme name for OAuth2). You simply have to specify the issuer name, realm and shared signature key: config.Handler.AddSimpleWebTokenHandler(     "Bearer",     http://identity.thinktecture.com/trust,     Constants.Realm,     "Dc9Mpi3jaaaUpBQpa/4R7XtUsa3D/ALSjTVvK8IUZbg="); For certain integration scenarios it is very useful if your Web API can consume SAML tokens. This is also easily accomplishable. The following code uses the standard WIF API to configure the usual SAMLisms like issuer, audience, service certificate and certificate validation. Both SAML 1.1 and 2.0 are supported. var registry = new ConfigurationBasedIssuerNameRegistry(); registry.AddTrustedIssuer( "d1 c5 b1 25 97 d0 36 94 65 1c e2 64 fe 48 06 01 35 f7 bd db", "ADFS"); var adfsConfig = new SecurityTokenHandlerConfiguration(); adfsConfig.AudienceRestriction.AllowedAudienceUris.Add( new Uri(Constants.Realm)); adfsConfig.IssuerNameRegistry = registry; adfsConfig.CertificateValidator = X509CertificateValidator.None; // token decryption (read from configuration section) adfsConfig.ServiceTokenResolver = FederatedAuthentication.ServiceConfiguration.CreateAggregateTokenResolver(); config.Handler.AddSaml11SecurityTokenHandler("SAML", adfsConfig); Claims Transformation After successful authentication, if configured, the standard WIF ClaimsAuthenticationManager is called to run claims transformation and validation logic. This stage is used to transform the “technical” claims from the security token into application claims. You can either have a separate transformation logic, or share on e.g. with the containing web application. That’s just a matter of configuration. Adding the authentication handler to a Web API application In the spirit of Web API this is done in code, e.g. global.asax for web hosting: protected void Application_Start() {     AreaRegistration.RegisterAllAreas();     ConfigureApis(GlobalConfiguration.Configuration);     RegisterGlobalFilters(GlobalFilters.Filters);     RegisterRoutes(RouteTable.Routes);     BundleTable.Bundles.RegisterTemplateBundles(); } private void ConfigureApis(HttpConfiguration configuration) {     configuration.MessageHandlers.Add( new AuthenticationHandler(ConfigureAuthentication())); } private AuthenticationConfiguration ConfigureAuthentication() {     var config = new AuthenticationConfiguration     {         // sample claims transformation for consultants sample, comment out to see raw claims         ClaimsAuthenticationManager = new ApiClaimsTransformer(),         // value of the www-authenticate header, // if not set, the first scheme added to the handler collection is used         DefaultAuthenticationScheme = "Basic"     };     // add token handlers - see above     return config; } You can find the full source code and some samples here. In the next post I will describe some of the samples in the download, and then move on to authorization. HTH

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• HTG Explains: Should You Build Your Own PC?

  - by Chris Hoffman

  There was a time when every geek seemed to build their own PC. While the masses bought eMachines and Compaqs, geeks built their own more powerful and reliable desktop machines for cheaper. But does this still make sense? Building your own PC still offers as much flexibility in component choice as it ever did, but prebuilt computers are available at extremely competitive prices. Building your own PC will no longer save you money in most cases. The Rise of Laptops It’s impossible to look at the decline of geeks building their own PCs without considering the rise of laptops. There was a time when everyone seemed to use desktops — laptops were more expensive and significantly slower in day-to-day tasks. With the diminishing importance of computing power — nearly every modern computer has more than enough power to surf the web and use typical programs like Microsoft Office without any trouble — and the rise of laptop availability at nearly every price point, most people are buying laptops instead of desktops. And, if you’re buying a laptop, you can’t really build your own. You can’t just buy a laptop case and start plugging components into it — even if you could, you would end up with an extremely bulky device. Ultimately, to consider building your own desktop PC, you have to actually want a desktop PC. Most people are better served by laptops. Benefits to PC Building The two main reasons to build your own PC have been component choice and saving money. Building your own PC allows you to choose all the specific components you want rather than have them chosen for you. You get to choose everything, including the PC’s case and cooling system. Want a huge case with room for a fancy water-cooling system? You probably want to build your own PC. In the past, this often allowed you to save money — you could get better deals by buying the components yourself and combining them, avoiding the PC manufacturer markup. You’d often even end up with better components — you could pick up a more powerful CPU that was easier to overclock and choose more reliable components so you wouldn’t have to put up with an unstable eMachine that crashed every day. PCs you build yourself are also likely more upgradable — a prebuilt PC may have a sealed case and be constructed in such a way to discourage you from tampering with the insides, while swapping components in and out is generally easier with a computer you’ve built on your own. If you want to upgrade your CPU or replace your graphics card, it’s a definite benefit. Downsides to Building Your Own PC It’s important to remember there are downsides to building your own PC, too. For one thing, it’s just more work — sure, if you know what you’re doing, building your own PC isn’t that hard. Even for a geek, researching the best components, price-matching, waiting for them all to arrive, and building the PC just takes longer. Warranty is a more pernicious problem. If you buy a prebuilt PC and it starts malfunctioning, you can contact the computer’s manufacturer and have them deal with it. You don’t need to worry about what’s wrong. If you build your own PC and it starts malfunctioning, you have to diagnose the problem yourself. What’s malfunctioning, the motherboard, CPU, RAM, graphics card, or power supply? Each component has a separate warranty through its manufacturer, so you’ll have to determine which component is malfunctioning before you can send it off for replacement. Should You Still Build Your Own PC? Let’s say you do want a desktop and are willing to consider building your own PC. First, bear in mind that PC manufacturers are buying in bulk and getting a better deal on each component. They also have to pay much less for a Windows license than the $120 or so it would cost you to to buy your own Windows license. This is all going to wipe out the cost savings you’ll see — with everything all told, you’ll probably spend more money building your own average desktop PC than you would picking one up from Amazon or the local electronics store. If you’re an average PC user that uses your desktop for the typical things, there’s no money to be saved from building your own PC. But maybe you’re looking for something higher end. Perhaps you want a high-end gaming PC with the fastest graphics card and CPU available. Perhaps you want to pick out each individual component and choose the exact components for your gaming rig. In this case, building your own PC may be a good option. As you start to look at more expensive, high-end PCs, you may start to see a price gap — but you may not. Let’s say you wanted to blow thousands of dollars on a gaming PC. If you’re looking at spending this kind of money, it would be worth comparing the cost of individual components versus a prebuilt gaming system. Still, the actual prices may surprise you. For example, if you wanted to upgrade Dell’s $2293 Alienware Aurora to include a second NVIDIA GeForce GTX 780 graphics card, you’d pay an additional $600 on Alienware’s website. The same graphics card costs $650 on Amazon or Newegg, so you’d be spending more money building the system yourself. Why? Dell’s Alienware gets bulk discounts you can’t get — and this is Alienware, which was once regarded as selling ridiculously overpriced gaming PCs to people who wouldn’t build their own. Building your own PC still allows you to get the most freedom when choosing and combining components, but this is only valuable to a small niche of gamers and professional users — most people, even average gamers, would be fine going with a prebuilt system. If you’re an average person or even an average gamer, you’ll likely find that it’s cheaper to purchase a prebuilt PC rather than assemble your own. Even at the very high end, components may be more expensive separately than they are in a prebuilt PC. Enthusiasts who want to choose all the individual components for their dream gaming PC and want maximum flexibility may want to build their own PCs. Even then, building your own PC these days is more about flexibility and component choice than it is about saving money. In summary, you probably shouldn’t build your own PC. If you’re an enthusiast, you may want to — but only a small minority of people would actually benefit from building their own systems. Feel free to compare prices, but you may be surprised which is cheaper. Image Credit: Richard Jones on Flickr, elPadawan on Flickr, Richard Jones on Flickr     

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• PostSharp, Obfuscation, and IL

  - by Simon Cooper

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day!

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• PostSharp, Obfuscation, and IL

  - by simonc

  Aspect-oriented programming (AOP) is a relatively new programming paradigm. Originating at Xerox PARC in 1994, the paradigm was first made available for general-purpose development as an extension to Java in 2001. From there, it has quickly been adapted for use in all the common languages used today. In the .NET world, one of the primary AOP toolkits is PostSharp. Attributes and AOP Normally, attributes in .NET are entirely a metadata construct. Apart from a few special attributes in the .NET framework, they have no effect whatsoever on how a class or method executes within the CLR. Only by using reflection at runtime can you access any attributes declared on a type or type member. PostSharp changes this. By declaring a custom attribute that derives from PostSharp.Aspects.Aspect, applying it to types and type members, and running the resulting assembly through the PostSharp postprocessor, you can essentially declare 'clever' attributes that change the behaviour of whatever the aspect has been applied to at runtime. A simple example of this is logging. By declaring a TraceAttribute that derives from OnMethodBoundaryAspect, you can automatically log when a method has been executed: public class TraceAttribute : PostSharp.Aspects.OnMethodBoundaryAspect { public override void OnEntry(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Entering {0}.{1}.", method.DeclaringType.FullName, method.Name)); } public override void OnExit(MethodExecutionArgs args) { MethodBase method = args.Method; System.Diagnostics.Trace.WriteLine( String.Format( "Leaving {0}.{1}.", method.DeclaringType.FullName, method.Name)); } } [Trace] public void MethodToLog() { ... } Now, whenever MethodToLog is executed, the aspect will automatically log entry and exit, without having to add the logging code to MethodToLog itself. PostSharp Performance Now this does introduce a performance overhead - as you can see, the aspect allows access to the MethodBase of the method the aspect has been applied to. If you were limited to C#, you would be forced to retrieve each MethodBase instance using Type.GetMethod(), matching on the method name and signature. This is slow. Fortunately, PostSharp is not limited to C#. It can use any instruction available in IL. And in IL, you can do some very neat things. Ldtoken C# allows you to get the Type object corresponding to a specific type name using the typeof operator: Type t = typeof(Random); The C# compiler compiles this operator to the following IL: ldtoken [mscorlib]System.Random call class [mscorlib]System.Type [mscorlib]System.Type::GetTypeFromHandle( valuetype [mscorlib]System.RuntimeTypeHandle) The ldtoken instruction obtains a special handle to a type called a RuntimeTypeHandle, and from that, the Type object can be obtained using GetTypeFromHandle. These are both relatively fast operations - no string lookup is required, only direct assembly and CLR constructs are used. However, a little-known feature is that ldtoken is not just limited to types; it can also get information on methods and fields, encapsulated in a RuntimeMethodHandle or RuntimeFieldHandle: // get a MethodBase for String.EndsWith(string) ldtoken method instance bool [mscorlib]System.String::EndsWith(string) call class [mscorlib]System.Reflection.MethodBase [mscorlib]System.Reflection.MethodBase::GetMethodFromHandle( valuetype [mscorlib]System.RuntimeMethodHandle) // get a FieldInfo for the String.Empty field ldtoken field string [mscorlib]System.String::Empty call class [mscorlib]System.Reflection.FieldInfo [mscorlib]System.Reflection.FieldInfo::GetFieldFromHandle( valuetype [mscorlib]System.RuntimeFieldHandle) These usages of ldtoken aren't usable from C# or VB, and aren't likely to be added anytime soon (Eric Lippert's done a blog post on the possibility of adding infoof, methodof or fieldof operators to C#). However, PostSharp deals directly with IL, and so can use ldtoken to get MethodBase objects quickly and cheaply, without having to resort to string lookups. The kicker However, there are problems. Because ldtoken for methods or fields isn't accessible from C# or VB, it hasn't been as well-tested as ldtoken for types. This has resulted in various obscure bugs in most versions of the CLR when dealing with ldtoken and methods, and specifically, generic methods and methods of generic types. This means that PostSharp was behaving incorrectly, or just plain crashing, when aspects were applied to methods that were generic in some way. So, PostSharp has to work around this. Without using the metadata tokens directly, the only way to get the MethodBase of generic methods is to use reflection: Type.GetMethod(), passing in the method name as a string along with information on the signature. Now, this works fine. It's slower than using ldtoken directly, but it works, and this only has to be done for generic methods. Unfortunately, this poses problems when the assembly is obfuscated. PostSharp and Obfuscation When using ldtoken, obfuscators don't affect how PostSharp operates. Because the ldtoken instruction directly references the type, method or field within the assembly, it is unaffected if the name of the object is changed by an obfuscator. However, the indirect loading used for generic methods was breaking, because that uses the name of the method when the assembly is put through the PostSharp postprocessor to lookup the MethodBase at runtime. If the name then changes, PostSharp can't find it anymore, and the assembly breaks. So, PostSharp needs to know about any changes an obfuscator does to an assembly. The way PostSharp does this is by adding another layer of indirection. When PostSharp obfuscation support is enabled, it includes an extra 'name table' resource in the assembly, consisting of a series of method & type names. When PostSharp needs to lookup a method using reflection, instead of encoding the method name directly, it looks up the method name at a fixed offset inside that name table: MethodBase genericMethod = typeof(ContainingClass).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: get_Prop1 21: set_Prop1 22: DoFoo 23: GetWibble When the assembly is later processed by an obfuscator, the obfuscator can replace all the method and type names within the name table with their new name. That way, the reflection lookups performed by PostSharp will now use the new names, and everything will work as expected: MethodBase genericMethod = typeof(#kGy).GetMethod(GetNameAtIndex(22)); PostSharp.NameTable resource: ... 20: #kkA 21: #zAb 22: #EF5a 23: #2tg As you can see, this requires direct support by an obfuscator in order to perform these rewrites. Dotfuscator supports it, and now, starting with SmartAssembly 6.6.4, SmartAssembly does too. So, a relatively simple solution to a tricky problem, with some CLR bugs thrown in for good measure. You don't see those every day! Cross posted from Simple Talk.

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• Calculated Fields - Idiosyncracies

  - by PointsToShare

  © 2011 By: Dov Trietsch. All rights reserved Calculated Fields and some of their Idiosyncrasies Did you try to write a calculate field formula directly into the screen? Good Luck – You’ll need it! Calculated Fields are a sophisticated OOB feature of SharePoint, so you could think that they are best left to the end users – at least to the power users. But they reach their limits before the “Professionals “do, and the tough ones come back to us anyway. Back to business; the simpler the formula, the easier it is. Still, use your favorite editor to write it, then cut it and paste it to the ridiculously small window. What about complex formulae? Write them in steps! Here is a case in point and an idiosyncrasy or two. Our welders need to be certified and recertified every two years. Some of them are certifiable…., but I digress. To be certified you need to pass an eye exam, and two more tests – test A and test B. for each of those you have an expiry date. When renewed, each expiry date is advanced by two years from the date of renewal. My users wanted a visual clue so that when the supervisor looks at the list, she’ll have a KPI symbol telling her if anything expired (Red), is going to expire within the next 90 days (Yellow) or is not to be worried about (green). Not all the dates are filled and any blank date implies a complete lack of certification in the particular requirement. Obviously, I needed to figure the minimal of these 3 dates – a simple enough formula: =MIN([Date_EyeExam], {Date_TestA], [Date_TestB]). Aha! Here is idiosyncrasy #1. When one of the dates is a null, MIN(Date1, Date2) returns the non null date. Null is construed as “Far, far away”. The funny thing is that when you compare it to Today, the null is the lesser one. So a null it is less than today, but not when MIN is calculated. Now, to me the fact that the welder does not have an exam date, is synonymous with his exam being prehistoric, or at least past due. So here is what I did: Solution: Let’s set a blank date to 1/1/1800. How will we do that? Use the IF. IF([Field] rel relValue, TrueValue, FalseValue). rel is any relationship operator <, >, <=, >=, =, <>. If the field is related to the relValue as prescribed, the “IF” returns the TrueValue, otherwise it returns the FalseValue. Thus: =IF([SomeDate]="",1/1/1800,[SomeDate]) will return 1/1/1800 if the date is blank and the date itself if not. So, using this formula, if the welder missed an exam, the returned exam date will be far in the past. It would be nice if we could take such a formula and make it into a reusable function. Alas, here is a calculated field serious shortcoming: You cannot write subs and functions!! Aha, but we can use interim calculated fields! So let’s create 3 calculated fields as follows: 1: c_DateTestA as a calculated field of the date type, with the formula:  IF([Date_TestA]="",1/1/1800,[Date_TestA]) 2: c_DateTestB as a calculated field of the date type, with the formula:  IF([Date_TestB]="",1/1/1800,[Date_TestB]) 3: c_DateEyeExam as a calculated field of the date type, with the formula:  IF([Date_EyeExam]="",1/1/1800,[Date_EyeExam]) And now use these to get c_MinDate. This is again a calculated field of type date with the formula: MIN(c_DateTestA, cDateTestB, c_DateEyeExam) Note that I missed the square parentheses. In “properly named fields – where there are no embedded spaces, we don’t need the square parentheses. I actually strongly recommend using underscores in place of spaces in all the field names in your lists. Among other things, it makes using CAML much simpler. Now, we still need to apply the KPI to this minimal date. I am going to use the available KPI graphics that come with SharePoint and are always available in your 12 hive. "/_layouts/images/kpidefault-2.gif" is the Red KPI "/_layouts/images/kpidefault-1.gif" is the Yellow KPI "/_layouts/images/kpidefault-0.gif" is the Green KPI And here is the nested IF formula that will do the trick: =IF(c_MinDate<=Today,"/_layouts/images/kpidefault-2.gif", IF(cMinDate<Today+90,"/_layouts/images/kpidefault-1.gif","/_layouts/images/kpidefault-0.gif")) Nice! BUT when I tested, it did not work! This is Idiosyncrasy #2: A calculated field based on a calculated field based on a calculated field does not work. You have to stop at two levels! Back to the drawing board: We have to reduce by one level. How? We’ll eliminate the c_DateX items in the formula and replace them with the proper IF formulae. Notice that this needs to be done with precision. You are much better off in doing it in your favorite line editor, than inside the cramped space that SharePoint gives you. So here is the result: MIN(IF([Date_TestA]="",1/1/1800,[ Date_TestA]), IF([Date_TestB]="",1/1/1800,[ Date_TestB]), 1/1/1800), IF([Date_EyeExam]="",1/1/1800,[Date_EyeExam])) Note that I bolded the parentheses and painted them red. They have to match for this formula to work. Now we can leave the KPI formula as is and test again. This time with SUCCESS! Conclusion: build the inner functions first, and then embed them inside the outer formulae. Do this as long as necessary. Use your favorite line editor. Limit yourself to 2 levels. That’s all folks! Almost! As soon as I finished doing all of the above, my users added yet another level of complexity. They added another test, a test that must be passed, but never expires and asked for yet another KPI, this time in Black to denote that any test is not just past due, but altogether missing. I just finished this. Let’s hope it ends here! And OH, the formula  =IF(c_MinDate<=Today,"/_layouts/images/kpidefault-2.gif",IF(cMinDate<Today+90,"/_layouts/images/kpidefault-1.gif","/_layouts/images/kpidefault-0.gif")) Deals with “Today” and this is a subject deserving a discussion of its own!  That’s all folks?! (and this time I mean it)

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• How to Control Screen Layouts in LightSwitch

  - by ChrisD

  Visual Studio LightSwitch has a bunch of screen templates that you can use to quickly generate screens. They give you good starting points that you can customize further. When you add a new screen to your project you see a set of screen templates that you can choose from. These templates lay out all the related data you choose to put on a screen automatically for you. And don’t under estimate them; they do a great job of laying out controls in a smart way. For instance, a tab control will be used when you select more than one related set of data to display on a screen. However, you’re not limited to taking the layout as is. In fact, the screen designer is pretty flexible and allows you to create stacks of controls in a variety of configurations. You just need to visualize your screen as a series of containers that you can lay out in rows and columns. You then place controls or stacks of controls into these areas to align the screen exactly how you want. If you’re new in Visual Studio LightSwitch, you can see this tutorial. OK, Let’s start with a simple example. I have already designed my data entities for a simple order tracking system similar to the Northwind database. I also have added a Search Data  Screen to search my Products already. Now I will add a new Details Screen for my Products and make it the default screen via the “Add New Screen” dialog: The screen designer picks a simple layout for me based on the single entity I chose, in this case Product. Hit F5 to run the application, select a Product on the search screen to open the Product Details Screen. Notice that it’s pretty simple because my entity is simple. Click the “Customize” button in the top right of the screen so we can start tweaking it. The left side of the screen shows the containership of controls and data bindings (called the content tree) and the right side shows the live preview with data. Notice that we have a simple layout of two rows but only one row is populated (with a vertical stack of controls in this case). The bottom row is empty. You can envision the screen like this: Each container will display a group of data that you select. For instance in the above screen, the top row is set to a vertical stack control and the group of data to display is coming from Product. So when laying out screens you need to think in terms of containers of controls bound to groups of data. To change the data to which a container is bound, select the data item next to the container: You can select the “New Group” item in order to create more containers (or controls) within the current container. For instance to totally control the layout, select the Product in the top row and hit the delete key. This will delete the vertical stack and therefore all the controls on the screen. The content tree will still have two rows, but the rows are now both empty. If you want a layout of four containers (two rows and two columns) then select “New Group” for the data item and then change the vertical stack control to “Two Columns” for both of the rows as shown here: You can keep going on and on by selecting new groups and choosing between rows or columns. Here’s a layout with 8 containers, 4 rows and 2 columns: And here is a layout with 7 content areas; one row across the top of the screen and three rows with two columns below that: When you select Choose Content and select a data item like Product it will populate all the controls within the container (row or column in a vertical stack) however you have complete control on what to display within each group. You can delete fields you don’t want to display and/or change their controls. You can also change the size of controls and how they display by changing the settings in the properties window. If you are in the Screen Designer (and not the customization mode like we are here) you can also drag-drop data items from the left-hand side of the screen to the content tree. Note, however, that not all areas of the tree will allow you to drop a data item if there is a binding already set to a different set of data. For instance you can’t drop a Customer ID into the same group as a Product if they originate from different entities. To get around this, all you need to do is create a new group and content area as shown above. Let’s take a more complex example that deals with more than just product. I want to design a complex screen that displays Products and their Category, as well as all the OrderDetails for which that product is selected. This time I will create a new screen and select List and Details, select the Products screen data, and include the related OrderDetails. However I’m going to totally change the layout so that a Product grid is at the top left and below that is the selected Product detail. Below that will be the Category text fields and image in two columns below. On the right side I want the OrderDetails grid to take up the whole right side of the screen. All this can be done in customization mode while you’re debugging the application. To do this, I first deleted all the content items in the tree and then re-created the content tree as shown in the image below. I also set the image to be larger and the description textbox to be 5 rows using the property window below the live preview. I added the green lines to indicate the containers and show how it maps to the content tree (click to enlarge): I hope this demystifies the screen designer a little bit. Remember that screen templates are excellent starting points – you can take them as-is or customize them further. It takes a little fooling around with customizing screens to get them to do exactly what you want but there are a ton of possibilities once you get the hang of it. Stay tuned for more information on how to create your own screen templates that show up in the “Add New Screen” dialog. Enjoy! The tutorial that might be interested: Adding Custom Control In LightSwitch

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• Parallelism in .NET – Part 7, Some Differences between PLINQ and LINQ to Objects

  - by Reed

  In my previous post on Declarative Data Parallelism, I mentioned that PLINQ extends LINQ to Objects to support parallel operations.  Although nearly all of the same operations are supported, there are some differences between PLINQ and LINQ to Objects.  By introducing Parallelism to our declarative model, we add some extra complexity.  This, in turn, adds some extra requirements that must be addressed. In order to illustrate the main differences, and why they exist, let’s begin by discussing some differences in how the two technologies operate, and look at the underlying types involved in LINQ to Objects and PLINQ . LINQ to Objects is mainly built upon a single class: Enumerable.  The Enumerable class is a static class that defines a large set of extension methods, nearly all of which work upon an IEnumerable<T>.  Many of these methods return a new IEnumerable<T>, allowing the methods to be chained together into a fluent style interface.  This is what allows us to write statements that chain together, and lead to the nice declarative programming model of LINQ: double min = collection .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); .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; } Other LINQ variants work in a similar fashion.  For example, most data-oriented LINQ providers are built upon an implementation of IQueryable<T>, which allows the database provider to turn a LINQ statement into an underlying SQL query, to be performed directly on the remote database. PLINQ is similar, but instead of being built upon the Enumerable class, most of PLINQ is built upon a new static class: ParallelEnumerable.  When using PLINQ, you typically begin with any collection which implements IEnumerable<T>, and convert it to a new type using an extension method defined on ParallelEnumerable: AsParallel().  This method takes any IEnumerable<T>, and converts it into a ParallelQuery<T>, the core class for PLINQ.  There is a similar ParallelQuery class for working with non-generic IEnumerable implementations. This brings us to our first subtle, but important difference between PLINQ and LINQ – PLINQ always works upon specific types, which must be explicitly created. Typically, the type you’ll use with PLINQ is ParallelQuery<T>, but it can sometimes be a ParallelQuery or an OrderedParallelQuery<T>.  Instead of dealing with an interface, implemented by an unknown class, we’re dealing with a specific class type.  This works seamlessly from a usage standpoint – ParallelQuery<T> implements IEnumerable<T>, so you can always “switch back” to an IEnumerable<T>.  The difference only arises at the beginning of our parallelization.  When we’re using LINQ, and we want to process a normal collection via PLINQ, we need to explicitly convert the collection into a ParallelQuery<T> by calling AsParallel().  There is an important consideration here – AsParallel() does not need to be called on your specific collection, but rather any IEnumerable<T>.  This allows you to place it anywhere in the chain of methods involved in a LINQ statement, not just at the beginning.  This can be useful if you have an operation which will not parallelize well or is not thread safe.  For example, the following is perfectly valid, and similar to our previous examples: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); However, if SomeOperation() is not thread safe, we could just as easily do: double min = collection .Select(item => item.SomeOperation()) .AsParallel() .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .Min(item => item.PerformComputation()); In this case, we’re using standard LINQ to Objects for the Select(…) method, then converting the results of that map routine to a ParallelQuery<T>, and processing our filter (the Where method) and our aggregation (the Min method) in parallel. PLINQ also provides us with a way to convert a ParallelQuery<T> back into a standard IEnumerable<T>, forcing sequential processing via standard LINQ to Objects.  If SomeOperation() was thread-safe, but PerformComputation() was not thread-safe, we would need to handle this by using the AsEnumerable() method: double min = collection .AsParallel() .Select(item => item.SomeOperation()) .Where(item => item.SomeProperty > 6 && item.SomeProperty < 24) .AsEnumerable() .Min(item => item.PerformComputation()); Here, we’re converting our collection into a ParallelQuery<T>, doing our map operation (the Select(…) method) and our filtering in parallel, then converting the collection back into a standard IEnumerable<T>, which causes our aggregation via Min() to be performed sequentially. This could also be written as two statements, as well, which would allow us to use the language integrated syntax for the first portion: var tempCollection = from item in collection.AsParallel() let e = item.SomeOperation() where (e.SomeProperty > 6 && e.SomeProperty < 24) select e; double min = tempCollection.AsEnumerable().Min(item => item.PerformComputation()); This allows us to use the standard LINQ style language integrated query syntax, but control whether it’s performed in parallel or serial by adding AsParallel() and AsEnumerable() appropriately. The second important difference between PLINQ and LINQ deals with order preservation.  PLINQ, by default, does not preserve the order of of source collection. This is by design.  In order to process a collection in parallel, the system needs to naturally deal with multiple elements at the same time.  Maintaining the original ordering of the sequence adds overhead, which is, in many cases, unnecessary.  Therefore, by default, the system is allowed to completely change the order of your sequence during processing.  If you are doing a standard query operation, this is usually not an issue.  However, there are times when keeping a specific ordering in place is important.  If this is required, you can explicitly request the ordering be preserved throughout all operations done on a ParallelQuery<T> by using the AsOrdered() extension method.  This will cause our sequence ordering to be preserved. For example, suppose we wanted to take a collection, perform an expensive operation which converts it to a new type, and display the first 100 elements.  In LINQ to Objects, our code might look something like: // Using IEnumerable<SourceClass> collection IEnumerable<ResultClass> results = collection .Select(e => e.CreateResult()) .Take(100); If we just converted this to a parallel query naively, like so: IEnumerable<ResultClass> results = collection .AsParallel() .Select(e => e.CreateResult()) .Take(100); We could very easily get a very different, and non-reproducable, set of results, since the ordering of elements in the input collection is not preserved.  To get the same results as our original query, we need to use: IEnumerable<ResultClass> results = collection .AsParallel() .AsOrdered() .Select(e => e.CreateResult()) .Take(100); This requests that PLINQ process our sequence in a way that verifies that our resulting collection is ordered as if it were processed serially.  This will cause our query to run slower, since there is overhead involved in maintaining the ordering.  However, in this case, it is required, since the ordering is required for correctness. PLINQ is incredibly useful.  It allows us to easily take nearly any LINQ to Objects query and run it in parallel, using the same methods and syntax we’ve used previously.  There are some important differences in operation that must be considered, however – it is not a free pass to parallelize everything.  When using PLINQ in order to parallelize your routines declaratively, the same guideline I mentioned before still applies: Parallelization is something that should be handled with care and forethought, added by design, and not just introduced casually.

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• ASP.NET MVC Postbacks and HtmlHelper Controls ignoring Model Changes

  - by Rick Strahl

  So here's a binding behavior in ASP.NET MVC that I didn't really get until today: HtmlHelpers controls (like .TextBoxFor() etc.) don't bind to model values on Postback, but rather get their value directly out of the POST buffer from ModelState. Effectively it looks like you can't change the display value of a control via model value updates on a Postback operation. To demonstrate here's an example. I have a small section in a document where I display an editable email address: This is what the form displays on a GET operation and as expected I get the email value displayed in both the textbox and plain value display below, which reflects the value in the mode. I added a plain text value to demonstrate the model value compared to what's rendered in the textbox. The relevant markup is the email address which needs to be manipulated via the model in the Controller code. Here's the Razor markup: <div class="fieldcontainer"> <label> Email: &nbsp; <small>(username and <a href="http://gravatar.com">Gravatar</a> image)</small> </label> <div> @Html.TextBoxFor( mod=> mod.User.Email, new {type="email",@class="inputfield"}) @Model.User.Email </div> </div>   So, I have this form and the user can change their email address. On postback the Post controller code then asks the business layer whether the change is allowed. If it's not I want to reset the email address back to the old value which exists in the database and was previously store. The obvious thing to do would be to modify the model. Here's the Controller logic block that deals with that:// did user change email? if (!string.IsNullOrEmpty(oldEmail) && user.Email != oldEmail) { if (userBus.DoesEmailExist(user.Email)) { userBus.ValidationErrors.Add("New email address exists already. Please…"); user.Email = oldEmail; } else // allow email change but require verification by forcing a login user.IsVerified = false; }… model.user = user; return View(model); The logic is straight forward - if the new email address is not valid because it already exists I don't want to display the new email address the user entered, but rather the old one. To do this I change the value on the model which effectively does this:model.user.Email = oldEmail; return View(model); So when I press the Save button after entering in my new email address ([email protected]) here's what comes back in the rendered view: Notice that the textbox value and the raw displayed model value are different. The TextBox displays the POST value, the raw value displays the actual model value which are different. This means that MVC renders the textbox value from the POST data rather than from the view data when an Http POST is active. Now I don't know about you but this is not the behavior I expected - initially. This behavior effectively means that I cannot modify the contents of the textbox from the Controller code if using HtmlHelpers for binding. Updating the model for display purposes in a POST has in effect - no effect. (Apr. 25, 2012 - edited the post heavily based on comments and more experimentation) What should the behavior be? After getting quite a few comments on this post I quickly realized that the behavior I described above is actually the behavior you'd want in 99% of the binding scenarios. You do want to get the POST values back into your input controls at all times, so that the data displayed on a form for the user matches what they typed. So if an error occurs, the error doesn't mysteriously disappear getting replaced either with a default value or some value that you changed on the model on your own. Makes sense. Still it is a little non-obvious because the way you create the UI elements with MVC, it certainly looks like your are binding to the model value:@Html.TextBoxFor( mod=> mod.User.Email, new {type="email",@class="inputfield",required="required" }) and so unless one understands a little bit about how the model binder works this is easy to trip up. At least it was for me. Even though I'm telling the control which model value to bind to, that model value is only used initially on GET operations. After that ModelState/POST values provide the display value. Workarounds The default behavior should be fine for 99% of binding scenarios. But if you do need fix up values based on your model rather than the default POST values, there are a number of ways that you can work around this. Initially when I ran into this, I couldn't figure out how to set the value using code and so the simplest solution to me was simply to not use the MVC Html Helper for the specific control and explicitly bind the model via HTML markup and @Razor expression: <input type="text" name="User.Email" id="User_Email" value="@Model.User.Email" /> And this produces the right result. This is easy enough to create, but feels a little out of place when using the @Html helpers for everything else. As you can see by the difference in the name and id values, you also are forced to remember the naming conventions that MVC imposes in order for ModelBinding to work properly which is a pain to remember and set manually (name is the same as the property with . syntax, id replaces dots with underlines). Use the ModelState Some of my original confusion came because I didn't understand how the model binder works. The model binder basically maintains ModelState on a postback, which holds a value and binding errors for each of the Post back value submitted on the page that can be mapped to the model. In other words there's one ModelState entry for each bound property of the model. Each ModelState entry contains a value property that holds AttemptedValue and RawValue properties. The AttemptedValue is essentially the POST value retrieved from the form. The RawValue is the value that the model holds. When MVC binds controls like @Html.TextBoxFor() or @Html.TextBox(), it always binds values on a GET operation. On a POST operation however, it'll always used the AttemptedValue to display the control. MVC binds using the ModelState on a POST operation, not the model's value. So, if you want the behavior that I was expecting originally you can actually get it by clearing the ModelState in the controller code:ModelState.Clear(); This clears out all the captured ModelState values, and effectively binds to the model. Note this will produce very similar results - in fact if there are no binding errors you see exactly the same behavior as if binding from ModelState, because the model has been updated from the ModelState already and binding to the updated values most likely produces the same values you would get with POST back values. The big difference though is that any values that couldn't bind - like say putting a string into a numeric field - will now not display back the value the user typed, but the default field value or whatever you changed the model value to. This is the behavior I was actually expecting previously. But - clearing out all values might be a bit heavy handed. You might want to fix up one or two values in a model but rarely would you want the entire model to update from the model. So, you can also clear out individual values on an as needed basis:if (userBus.DoesEmailExist(user.Email)) { userBus.ValidationErrors.Add("New email address exists already. Please…"); user.Email = oldEmail; ModelState.Remove("User.Email"); } This allows you to remove a single value from the ModelState and effectively allows you to replace that value for display from the model. Why? While researching this I came across a post from Microsoft's Brad Wilson who describes the default binding behavior best in a forum post: The reason we use the posted value for editors rather than the model value is that the model may not be able to contain the value that the user typed. Imagine in your "int" editor the user had typed "dog". You want to display an error message which says "dog is not valid", and leave "dog" in the editor field. However, your model is an int: there's no way it can store "dog". So we keep the old value. If you don't want the old values in the editor, clear out the Model State. That's where the old value is stored and pulled from the HTML helpers. There you have it. It's not the most intuitive behavior, but in hindsight this behavior does make some sense even if at first glance it looks like you should be able to update values from the model. The solution of clearing ModelState works and is a reasonable one but you have to know about some of the innards of ModelState and how it actually works to figure that out.© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  MVC   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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• SQL SERVER – Guest Posts – Feodor Georgiev – The Context of Our Database Environment – Going Beyond the Internal SQL Server Waits – Wait Type – Day 21 of 28

  - by pinaldave

  This guest post is submitted by Feodor. Feodor Georgiev is a SQL Server database specialist with extensive experience of thinking both within and outside the box. He has wide experience of different systems and solutions in the fields of architecture, scalability, performance, etc. Feodor has experience with SQL Server 2000 and later versions, and is certified in SQL Server 2008. In this article Feodor explains the server-client-server process, and concentrated on the mutual waits between client and SQL Server. This is essential in grasping the concept of waits in a ‘global’ application plan. Recently I was asked to write a blog post about the wait statistics in SQL Server and since I had been thinking about writing it for quite some time now, here it is. It is a wide-spread idea that the wait statistics in SQL Server will tell you everything about your performance. Well, almost. Or should I say – barely. The reason for this is that SQL Server is always a part of a bigger system – there are always other players in the game: whether it is a client application, web service, any other kind of data import/export process and so on. In short, the SQL Server surroundings look like this: This means that SQL Server, aside from its internal waits, also depends on external waits and settings. As we can see in the picture above, SQL Server needs to have an interface in order to communicate with the surrounding clients over the network. For this communication, SQL Server uses protocol interfaces. I will not go into detail about which protocols are best, but you can read this article. Also, review the information about the TDS (Tabular data stream). As we all know, our system is only as fast as its slowest component. This means that when we look at our environment as a whole, the SQL Server might be a victim of external pressure, no matter how well we have tuned our database server performance. Let’s dive into an example: let’s say that we have a web server, hosting a web application which is using data from our SQL Server, hosted on another server. The network card of the web server for some reason is malfunctioning (think of a hardware failure, driver failure, or just improper setup) and does not send/receive data faster than 10Mbs. On the other end, our SQL Server will not be able to send/receive data at a faster rate either. This means that the application users will notify the support team and will say: “My data is coming very slow.” Now, let’s move on to a bit more exciting example: imagine that there is a similar setup as the example above – one web server and one database server, and the application is not using any stored procedure calls, but instead for every user request the application is sending 80kb query over the network to the SQL Server. (I really thought this does not happen in real life until I saw it one day.) So, what happens in this case? To make things worse, let’s say that the 80kb query text is submitted from the application to the SQL Server at least 100 times per minute, and as often as 300 times per minute in peak times. Here is what happens: in order for this query to reach the SQL Server, it will have to be broken into a of number network packets (according to the packet size settings) – and will travel over the network. On the other side, our SQL Server network card will receive the packets, will pass them to our network layer, the packets will get assembled, and eventually SQL Server will start processing the query – parsing, allegorizing, generating the query execution plan and so on. So far, we have already had a serious network overhead by waiting for the packets to reach our Database Engine. There will certainly be some processing overhead – until the database engine deals with the 80kb query and its 20 subqueries. The waits you see in the DMVs are actually collected from the point the query reaches the SQL Server and the packets are assembled. Let’s say that our query is processed and it finally returns 15000 rows. These rows have a certain size as well, depending on the data types returned. This means that the data will have converted to packages (depending on the network size package settings) and will have to reach the application server. There will also be waits, however, this time you will be able to see a wait type in the DMVs called ASYNC_NETWORK_IO. What this wait type indicates is that the client is not consuming the data fast enough and the network buffers are filling up. Recently Pinal Dave posted a blog on Client Statistics. What Client Statistics does is captures the physical flow characteristics of the query between the client(Management Studio, in this case) and the server and back to the client. As you see in the image, there are three categories: Query Profile Statistics, Network Statistics and Time Statistics. Number of server roundtrips–a roundtrip consists of a request sent to the server and a reply from the server to the client. For example, if your query has three select statements, and they are separated by ‘GO’ command, then there will be three different roundtrips. TDS Packets sent from the client – TDS (tabular data stream) is the language which SQL Server speaks, and in order for applications to communicate with SQL Server, they need to pack the requests in TDS packets. TDS Packets sent from the client is the number of packets sent from the client; in case the request is large, then it may need more buffers, and eventually might even need more server roundtrips. TDS packets received from server –is the TDS packets sent by the server to the client during the query execution. Bytes sent from client – is the volume of the data set to our SQL Server, measured in bytes; i.e. how big of a query we have sent to the SQL Server. This is why it is best to use stored procedures, since the reusable code (which already exists as an object in the SQL Server) will only be called as a name of procedure + parameters, and this will minimize the network pressure. Bytes received from server – is the amount of data the SQL Server has sent to the client, measured in bytes. Depending on the number of rows and the datatypes involved, this number will vary. But still, think about the network load when you request data from SQL Server. Client processing time – is the amount of time spent in milliseconds between the first received response packet and the last received response packet by the client. Wait time on server replies – is the time in milliseconds between the last request packet which left the client and the first response packet which came back from the server to the client. Total execution time – is the sum of client processing time and wait time on server replies (the SQL Server internal processing time) Here is an illustration of the Client-server communication model which should help you understand the mutual waits in a client-server environment. Keep in mind that a query with a large ‘wait time on server replies’ means the server took a long time to produce the very first row. This is usual on queries that have operators that need the entire sub-query to evaluate before they proceed (for example, sort and top operators). However, a query with a very short ‘wait time on server replies’ means that the query was able to return the first row fast. However a long ‘client processing time’ does not necessarily imply the client spent a lot of time processing and the server was blocked waiting on the client. It can simply mean that the server continued to return rows from the result and this is how long it took until the very last row was returned. The bottom line is that developers and DBAs should work together and think carefully of the resource utilization in the client-server environment. From experience I can say that so far I have seen only cases when the application developers and the Database developers are on their own and do not ask questions about the other party’s world. I would recommend using the Client Statistics tool during new development to track the performance of the queries, and also to find a synchronous way of utilizing resources between the client – server – client. Here is another example: think about similar setup as above, but add another server to the game. Let’s say that we keep our media on a separate server, and together with the data from our SQL Server we need to display some images on the webpage requested by our user. No matter how simple or complicated the logic to get the images is, if the images are 500kb each our users will get the page slowly and they will still think that there is something wrong with our data. Anyway, I don’t mean to get carried away too far from SQL Server. Instead, what I would like to say is that DBAs should also be aware of ‘the big picture’. I wrote a blog post a while back on this topic, and if you are interested, you can read it here about the big picture. And finally, here are some guidelines for monitoring the network performance and improving it: Run a trace and outline all queries that return more than 1000 rows (in Profiler you can actually filter and sort the captured trace by number of returned rows). This is not a set number; it is more of a guideline. The general thought is that no application user can consume that many rows at once. Ask yourself and your fellow-developers: ‘why?’. Monitor your network counters in Perfmon: Network Interface:Output queue length, Redirector:Network errors/sec, TCPv4: Segments retransmitted/sec and so on. Make sure to establish a good friendship with your network administrator (buy them coffee, for example J ) and get into a conversation about the network settings. Have them explain to you how the network cards are setup – are they standalone, are they ‘teamed’, what are the settings – full duplex and so on. Find some time to read a bit about networking. In this short blog post I hope I have turned your attention to ‘the big picture’ and the fact that there are other factors affecting our SQL Server, aside from its internal workings. As a further reading I would still highly recommend the Wait Stats series on this blog, also I would recommend you have the coffee break conversation with your network admin as soon as possible. This guest post is written by Feodor Georgiev. Read all the post in the Wait Types and Queue series. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, Readers Contribution, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL

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• Adventures in MVVM &ndash; My ViewModel Base

  - by Brian Genisio's House Of Bilz

  More Adventures in MVVM First, I’d like to say: THIS IS NOT A NEW MVVM FRAMEWORK. I tend to believe that MVVM support code should be specific to the system you are building and the developers working on it.  I have yet to find an MVVM framework that does everything I want it to without doing too much.  Don’t get me wrong… there are some good frameworks out there.  I just like to pick and choose things that make sense for me.  I’d also like to add that some of these features only work in WPF.  As of Silveright 4, they don’t support binding to dynamic properties, so some of the capabilities are lost. That being said, I want to share my ViewModel base class with the world.  I have had several conversations with people about the problems I have solved using this ViewModel base.  A while back, I posted an article about some experiments with a “Rails Inspired ViewModel”.  What followed from those ideas was a ViewModel base class that I take with me and use in my projects.  It has a lot of features, all designed to reduce the friction in writing view models. I have put the code out on Codeplex under the project: ViewModelSupport. Finally, this article focuses on the ViewModel and only glosses over the View and the Model.  Without all three, you don’t have MVVM.  But this base class is for the ViewModel, so that is what I am focusing on. Features: Automatic Command Plumbing Property Change Notification Strongly Typed Property Getter/Setters Dynamic Properties Default Property values Derived Properties Automatic Method Execution Command CanExecute Change Notification Design-Time Detection What about Silverlight? Automatic Command Plumbing This feature takes the plumbing out of creating commands.  The common pattern for commands in a ViewModel is to have an Execute method as well as an optional CanExecute method.  To plumb that together, you create an ICommand Property, and set it in the constructor like so: Before public class AutomaticCommandViewModel { public AutomaticCommandViewModel() { MyCommand = new DelegateCommand(Execute_MyCommand, CanExecute_MyCommand); } public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } public DelegateCommand MyCommand { get; private set; } } With the base class, this plumbing is automatic and the property (MyCommand of type ICommand) is created for you.  The base class uses the convention that methods be prefixed with Execute_ and CanExecute_ in order to be plumbed into commands with the property name after the prefix.  You are left to be expressive with your behavior without the plumbing.  If you are wondering how CanExecuteChanged is raised, see the later section “Command CanExecute Change Notification”. After public class AutomaticCommandViewModel : ViewModelBase { public void Execute_MyCommand() { // Do something } public bool CanExecute_MyCommand() { // Are we in a state to do something? return true; } }   Property Change Notification One thing that always kills me when implementing ViewModels is how to make properties that notify when they change (via the INotifyPropertyChanged interface).  There have been many attempts to make this more automatic.  My base class includes one option.  There are others, but I feel like this works best for me. The common pattern (without my base class) is to create a private backing store for the variable and specify a getter that returns the private field.  The setter will set the private field and fire an event that notifies the change, only if the value has changed. Before public class PropertyHelpersViewModel : INotifyPropertyChanged { private string text; public string Text { get { return text; } set { if(text != value) { text = value; RaisePropertyChanged("Text"); } } } protected void RaisePropertyChanged(string propertyName) { var handlers = PropertyChanged; if(handlers != null) handlers(this, new PropertyChangedEventArgs(propertyName)); } public event PropertyChangedEventHandler PropertyChanged; } This way of defining properties is error-prone and tedious.  Too much plumbing.  My base class eliminates much of that plumbing with the same functionality: After public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get<string>("Text"); } set { Set("Text", value);} } }   Strongly Typed Property Getters/Setters It turns out that we can do better than that.  We are using a strongly typed language where the use of “Magic Strings” is often frowned upon.  Lets make the names in the getters and setters strongly typed: A refinement public class PropertyHelpersViewModel : ViewModelBase { public string Text { get { return Get(() => Text); } set { Set(() => Text, value); } } }   Dynamic Properties In C# 4.0, we have the ability to program statically OR dynamically.  This base class lets us leverage the powerful dynamic capabilities in our ecosystem. (This is how the automatic commands are implemented, BTW)  By calling Set(“Foo”, 1), you have now created a dynamic property called Foo.  It can be bound against like any static property.  The opportunities are endless.  One great way to exploit this behavior is if you have a customizable view engine with templates that bind to properties defined by the user.  The base class just needs to create the dynamic properties at runtime from information in the model, and the custom template can bind even though the static properties do not exist. All dynamic properties still benefit from the notifiable capabilities that static properties do. For any nay-sayers out there that don’t like using the dynamic features of C#, just remember this: the act of binding the View to a ViewModel is dynamic already.  Why not exploit it?  Get over it :) Just declare the property dynamically public class DynamicPropertyViewModel : ViewModelBase { public DynamicPropertyViewModel() { Set("Foo", "Bar"); } } Then reference it normally <TextBlock Text="{Binding Foo}" />   Default Property Values The Get() method also allows for default properties to be set.  Don’t set them in the constructor.  Set them in the property and keep the related code together: public string Text { get { return Get(() => Text, "This is the default value"); } set { Set(() => Text, value);} }   Derived Properties This is something I blogged about a while back in more detail.  This feature came from the chaining of property notifications when one property affects the results of another, like this: Before public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); RaisePropertyChanged("Percentage"); RaisePropertyChanged("Output"); } } public int Percentage { get { return (int)(100 * Score); } } public string Output { get { return "You scored " + Percentage + "%."; } } } The problem is: The setter for Score has to be responsible for notifying the world that Percentage and Output have also changed.  This, to me, is backwards.    It certainly violates the “Single Responsibility Principle.” I have been bitten in the rear more than once by problems created from code like this.  What we really want to do is invert the dependency.  Let the Percentage property declare that it changes when the Score Property changes. After public class DependantPropertiesViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public int Percentage { get { return (int)(100 * Score); } } [DependsUpon("Percentage")] public string Output { get { return "You scored " + Percentage + "%."; } } }   Automatic Method Execution This one is extremely similar to the previous, but it deals with method execution as opposed to property.  When you want to execute a method triggered by property changes, let the method declare the dependency instead of the other way around. Before public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); WhenScoreChanges(); } } public void WhenScoreChanges() { // Handle this case } } After public class DependantMethodsViewModel : ViewModelBase { public double Score { get { return Get(() => Score); } set { Set(() => Score, value); } } [DependsUpon("Score")] public void WhenScoreChanges() { // Handle this case } }   Command CanExecute Change Notification Back to Commands.  One of the responsibilities of commands that implement ICommand – it must fire an event declaring that CanExecute() needs to be re-evaluated.  I wanted to wait until we got past a few concepts before explaining this behavior.  You can use the same mechanism here to fire off the change.  In the CanExecute_ method, declare the property that it depends upon.  When that property changes, the command will fire a CanExecuteChanged event, telling the View to re-evaluate the state of the command.  The View will make appropriate adjustments, like disabling the button. DependsUpon works on CanExecute methods as well public class CanExecuteViewModel : ViewModelBase { public void Execute_MakeLower() { Output = Input.ToLower(); } [DependsUpon("Input")] public bool CanExecute_MakeLower() { return !string.IsNullOrWhiteSpace(Input); } public string Input { get { return Get(() => Input); } set { Set(() => Input, value);} } public string Output { get { return Get(() => Output); } set { Set(() => Output, value); } } }   Design-Time Detection If you want to add design-time data to your ViewModel, the base class has a property that lets you ask if you are in the designer.  You can then set some default values that let your designer see what things might look like in runtime. Use the IsInDesignMode property public DependantPropertiesViewModel() { if(IsInDesignMode) { Score = .5; } }   What About Silverlight? Some of the features in this base class only work in WPF.  As of version 4, Silverlight does not support binding to dynamic properties.  This, in my opinion, is a HUGE limitation.  Not only does it keep you from using many of the features in this ViewModel, it also keeps you from binding to ViewModels designed in IronRuby.  Does this mean that the base class will not work in Silverlight?  No.  Many of the features outlined in this article WILL work.  All of the property abstractions are functional, as long as you refer to them statically in the View.  This, of course, means that the automatic command hook-up doesn’t work in Silverlight.  You need to plumb it to a static property in order for the Silverlight View to bind to it.  Can I has a dynamic property in SL5?     Good to go? So, that concludes the feature explanation of my ViewModel base class.  Feel free to take it, fork it, whatever.  It is hosted on CodePlex.  When I find other useful additions, I will add them to the public repository.  I use this base class every day.  It is mature, and well tested.  If, however, you find any problems with it, please let me know!  Also, feel free to suggest patches to me via the CodePlex site.  :)

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• Entity Framework v1 &hellip; Brief Synopsis and Tips &ndash; Part 2

  - by Rohit Gupta

  Using Entity Framework with ASMX Web sErvices and WCF Web Service: If you use ASMX WebService to expose Entity objects from Entity Framework... then the ASMX Webservice does not  include object graphs, one work around is to use Facade pattern or to use WCF Service. The other important aspect of using ASMX Web Services along with Entity Framework is that the ASMX Client is not aware of the existence of EF v1 since the client solely deals with C# objects (not EntityObjects or ObjectContext). Since the client is not aware of the ObjectContext hence the client cannot participate in change tracking since the client only receives the Current Values and not the Orginal values when the service sends the the Entity objects to the client. Thus there are 2 drawbacks to using EntityFramework with ASMX Web Service: 1. Object state is not maintained... so to overcome this limitation we need insert/update single entity at a time and retrieve the original values for the entity being updated on the server/service end before calling Save Changes. 2. ASMX does not maintain object graphs... i.e. Customer.Reservations or Customer.Reservations.Trip relationships are not maintained. Thus you need to send these relationships separately from service to client. WCF Web Service overcomes the object graph limitation of ASMX Web Service, but we need to insure that we are populating all the non-null scalar properties of all the objects in the object graph before calling Update. WCF Web service still cannot overcome the second limitation of tracking changes to entities at the client end. Also note that the "Customer" class in the Client is very different from the "Customer" class in the Entity Framework Model Entities. They are incompatible with each other hence we cannot cast one to the other. However the .NET Framework translates the client "Customer" Entity to the EFv1 Model "customer" Entity once the entity is serialzed back on the ASMX server end. If you need change tracking enabled on the client then we need to use WCF Data Services which is available with VS 2010. ====================================================================================================== In WCF when adding an object that has relationships, the framework assumes that every object in the object graph needs to be added to store. for e.g. in a Customer.Reservations.Trip object graph, when a Customer Entity is added to the store, the EFv1 assumes that it needs to a add a Reservations collection and also Trips for each Reservation. Thus if we need to use existing Trips for reservations then we need to insure that we null out the Trip object reference from Reservations and set the TripReference to the EntityKey of the desired Trip instead. ====================================================================================================== Understanding Relationships and Associations in EFv1 The Golden Rule of EF is that it does not load entities/relationships unless you ask it to explicitly do so. However there is 1 exception to this rule. This exception happens when you attach/detach entities from the ObjectContext. If you detach an Entity in a ObjectGraph from the ObjectContext, then the ObjectContext removes the ObjectStateEntry for this Entity and all the relationship Objects associated with this Entity. For e.g. in a Customer.Order.OrderDetails if the Customer Entity is detached from the ObjectContext then you cannot traverse to the Order and OrderDetails Entities (that still exist in the ObjectContext) from the Customer Entity(which does not exist in the Object Context) Conversely, if you JOIN a entity that is not in the ObjectContext with a Entity that is in the ObjContext then the First Entity will automatically be added to the ObjContext since relationships for the 2 Entities need to exist in the ObjContext. ========================================================= You cannot attach an EntityCollection to an entity through its navigation property for e.g. you cannot code myContact.Addresses = myAddressEntityCollection ========================================================== Cascade Deletes in EDM: The Designer does not support specifying cascase deletes for a Entity. To enable cascasde deletes on a Entity in EDM use the Association definition in CSDL for the Entity. for e.g. SalesOrderDetail (SOD) has a Foreign Key relationship with SalesOrderHeader (SalesOrderHeader 1 : SalesOrderDetail *) if you specify a cascade Delete on SalesOrderHeader Entity then calling deleteObject on SalesOrderHeader (SOH) Entity will send delete commands for SOH record and all the SOD records that reference the SOH record. ========================================================== As a good design practise, if you use Cascade Deletes insure that Cascade delete facet is used both in the EDM as well as in the database. Even though it is not absolutely mandatory to have Cascade deletes on both Database and EDM (since you can see that just the Cascade delete spec on the SOH Entity in EDM will insure that SOH record and all related SOD records will be deleted from the database ... even though you dont have cascade delete configured in the database in the SOD table) ============================================================== Maintaining relationships in Code When Setting a Navigation property of a Entity (for e.g. setting the Contact Navigation property of Address Entity) the following rules apply : If both objects are detached, no relationship object will be created. You are simply setting a property the CLR way. If both objects are attached, a relationship object will be created. If only one of the objects is attached, the other will become attached and a relationship object will be created. If that detached object is new, when it is attached to the context its EntityState will be Added. One important rule to remember regarding synchronizing the EntityReference.Value and EntityReference.EntityKey properties is that when attaching an Entity which has a EntityReference (e.g. Address Entity with ContactReference) the Value property will take precedence and if the Value and EntityKey are out of sync, the EntityKey will be updated to match the Value. ====================================================== If you call .Load() method on a detached Entity then the .Load() operation will throw an exception. There is one exception to this rule. If you load entities using MergeOption.NoTracking, you will be able to call .Load() on such entities since these Entities are accessible by the ObjectContext. So the bottomline is that we need Objectontext to be able to call .Load() method to do deffered loading on EntityReference or EntityCollection. Another rule to remember is that you cannot call .Load() on entities that have a EntityState.Added State since the ObjectContext uses the EntityKey of the Primary (Parent) Entity when loading the related (Child) Entity (and not the EntityKey of the child (even if the EntityKey of the child is present before calling .Load()) ====================================================== You can use ObjContext.Add() to add a entity to the ObjContext and set the EntityState of the new Entity to EntityState.Added. here no relationships are added/updated. You can also use EntityCollection.Add() method to add an entity to another entity's related EntityCollection for e.g. contact has a Addresses EntityCollection so to add a new address use contact.Addresses.Add(newAddress) to add a new address to the Addresses EntityCollection. Note that if the entity does not already exist in the ObjectContext then calling contact.Addresses.Add(myAddress) will cause a new Address Entity to be added to the ObjContext with EntityState.Added and it will also add a RelationshipEntry (a relationship object) with EntityState.Added which connects the Contact (contact) with the new address newAddress. Note that if the entity already exists in the Objectcontext (being part theOtherContact.Addresses Collection), then calling contact.Addresses.Add(existingAddress) will add 2 RelationshipEntry objects to the ObjectStateEntry Collection, one with EntityState.Deleted and the other with EntityState.Added. This implies that the existingAddress Entity is removed from the theOtherContact.Addresses Collection and Added to the contact.Addresses Collection..effectively reassigning the address entity from the theOtherContact to "contact". This is called moving an existing entity to a new object graph. ====================================================== You usually use ObjectContext.Attach() and EntityCollection.Attach() methods usually when you need to reconstruct the ObjectGraph after deserializing the objects as received from a ASMX Web Service Client. Attach is usually used to connect existing Entities in the ObjectContext. When EntityCollection.Attach() is called the EntityState of the RelationshipEntry (the relationship object) remains as EntityState.unchanged whereas when EntityCollection.Add() method is called the EntityState of the relationship object changes to EntityState.Added or EntityState.Deleted as the situation demands. ========================================================= LINQ To Entities Tips: Select Many does Inner Join by default.   for e.g. from c in Contact from a in c.Address select c ... this will do a Inner Join between the Contacts and Addresses Table and return only those Contacts that have a Address. ======================================================== Group Joins Do LEFT Join by default. e.g. from a in Address join c in Contact ON a.Contact.ContactID == c.ContactID Into g WHERE a.CountryRegion == "US" select g; This query will do a left join on the Contact table and return contacts that have a address in "US" region The following query : from c in Contact join a in Address.Where(a1 => a1.CountryRegion == "US") on c.ContactID  equals a.Contact.ContactID into addresses select new {c, addresses} will do a left join on the Address table and return All Contacts. In these Contacts only those will have its Address EntityCollection Populated which have a Address in the "US" region, the other contacts will have 0 Addresses in the Address collection (even if addresses for those contacts exist in the database but are in a different region) ======================================================== Linq to Entities does not support DefaultIfEmpty().... instead use .Include("Address") Query Builder method to do a Left JOIN or use Group Joins if you need more control like Filtering on the Address EntityCollection of Contact Entity =================================================================== Use CreateSourceQuery() on the EntityReference or EntityCollection if you need to add filters during deferred loading of Entities (Deferred loading in EFv1 happens when you call Load() method on the EntityReference or EntityCollection. for e.g. var cust=context.Contacts.OfType<Customer>().First(); var sq = cust.Reservations.CreateSourceQuery().Where(r => r.ReservationDate > new DateTime(2008,1,1)); cust.Reservations.Attach(sq); This populates only those reservations that are older than Jan 1 2008. This is the only way (in EFv1) to Attach a Range of Entities to a EntityCollection using the Attach() method ================================================================== If you need to get the Foreign Key value for a entity e.g. to get the ContactID value from a Address Entity use this :                                address.ContactReference.EntityKey.EntityKeyValues.Where(k=> k.Key == "ContactID")

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• Issuing Current Time Increments in StreamInsight (A Practical Example)

  The issuing of a Current Time Increment, Cti, in StreamInsight is very definitely one of the most important concepts to learn if you want your Streams to be responsive. A full discussion of how to issue Ctis is beyond the scope of this article but a very good explanation in addition to Books Online can be found in these three articles by a member of the StreamInsight team at Microsoft, Ciprian Gerea. Time in StreamInsight Series http://blogs.msdn.com/b/streaminsight/archive/2010/07/23/time-in-streaminsight-i.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/07/30/time-in-streaminsight-ii.aspx http://blogs.msdn.com/b/streaminsight/archive/2010/08/03/time-in-streaminsight-iii.aspx A lot of the problems I see with unresponsive or stuck streams on the MSDN Forums are to do with how Ctis are enqueued or in a lot of cases not enqueued. If you enqueue events and never enqueue a Cti then StreamInsight will be perfectly happy. You, on the other hand, will never see data on the output as you have not told StreamInsight to flush the stream. This article deals with a specific implementation problem I had recently whilst working on a StreamInsight project. I look at some possible options and discuss why they would not work before showing the way I solved the problem. The stream of data I was dealing with on this project was very bursty that is to say when events were flowing they came through very quickly and in large numbers (1000 events/sec), but when the stream calmed down it could be a few seconds between each event. When enqueuing events into the StreamInsight engne it is best practice to do so with a StartTime that is given to you by the system producing the event . StreamInsight processes events and it doesn't matter whether those events are being pushed into the engine by a source system or the events are being read from something like a flat file in a directory somewhere. You can apply the same logic and temporal algebra to both situations. Reading from a file is an excellent example of where the time of the event on the source itself is very important. We could be reading that file a long time after it was written. Being able to read the StartTime from the events allows us to define windows that will hold the correct sets of events. I was able to do this with my stream but this is where my problems started. Below is a very simple script to create a SQL Server table and populate it with sample data that will show exactly the problem I had. CREATE TABLE [dbo].[t] ( [c1] [int] PRIMARY KEY, [c2] [datetime] NULL ) INSERT t VALUES (1,'20100810'),(2,'20100810'),(3,'20100810') Column c2 defines the StartTime of the event on the source and as you can see the values in all 3 rows of data is the same. If we read Ciprian’s articles we know that we can define how Ctis get injected into the stream in 3 different places The Stream Definition The Input Factory The Input Adapter I personally have always been a fan of enqueing Ctis through the factory. Below is code typical of what I would use to do this On the class itself I do some inheriting public class SimpleInputFactory : ITypedInputAdapterFactory<SimpleInputConfig>, ITypedDeclareAdvanceTimeProperties<SimpleInputConfig> And then I implement the following function public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.FromTicks(-1)), AdvanceTimePolicy.Adjust); } The configInfo .CtiFrequency property is a value I pass through to define after how many events I want a Cti to be injected and this in turn will flush through the stream of data. I usually pass a value of 1 for this setting. The second parameter determines the CTI timestamp in terms of a delay relative to the events. -1 ticks in the past results in 1 tick in the future, i.e., ahead of the event. The problem with this method though is that if consecutive events have the same StartTime then only one of those events will be enqueued. In this example I use the following to define how I assign the StartTime of my events currEvent.StartTime = (DateTimeOffset)dt.c2; If I go ahead and run my StreamInsight process with this configuration i can see on the output adapter that two events have been removed To see this in a little more depth I can use the StreamInsight Debugger and see what happens internally. What is happening here is that the first event arrives and a Cti is injected with a time of 1 tick after the StartTime of that event (Also the EndTime of the event). The second event arrives and it has a StartTime of before the Cti and even though we specified AdvanceTimePolicy.Adjust on the factory we know that a point event can never be adjusted like this and the event is dropped. The same happens for the third event as well (The second and third events get trumped by the Cti). For a more detailed discussion of why this happens look here http://www.sqlis.com/sqlis/post/AdvanceTimePolicy-and-Point-Event-Streams-In-StreamInsight.aspx We end up with a single event being pushed into the output adapter and our result now makes sense. The next way I tried to solve this problem by changing the value of the second parameter to TimeSpan.Zero Here is how my factory code now looks public AdapterAdvanceTimeSettings DeclareAdvanceTimeProperties<TPayload>(SimpleInputConfig configInfo, EventShape eventShape) { return new AdapterAdvanceTimeSettings( new AdvanceTimeGenerationSettings(configInfo.CtiFrequency, TimeSpan.Zero), AdvanceTimePolicy.Adjust); } What I am doing here is declaring a policy that says inject a Cti together with every event and stamp it with a StartTime that is equal to the start time of the event itself (TimeSpan.Zero). This method has plus points as well as a downside. The upside is that no events will be lost by having the same StartTime as previous events. The Downside is that because the Cti is declared with the StartTime of the event itself then it does not actually flush that particular event because in the StreamInsight algebra, a Cti commits only those events that occurred strictly before them. To flush the events we need a Cti to be enqueued with a greater StartTime than the events themselves. Here is what happened when I ran this configuration As you can see all we got through was the Cti and none of the events. The debugger output shows the stamps on the Cti and the events themselves. Because the Cti issued has the same timestamp (StartTime) as the events then none of the events get flushed. I was nearly there but not quite. Because my stream was bursty it was possible that the next event would not come along for a few seconds and this was far too long for an event to be enqueued and not be flushed to the output adapter. I needed another solution. Two possible solutions crossed my mind although only one of them made sense when I explored it some more. Where multiple events have the same StartTime I could add 1 tick to the first event, two to the second, three to third etc thereby giving them unique StartTime values. Add a timer to manually inject Ctis The problem with the first implementation is that I would be giving the events a new StartTime. This would cause me the following problems If I want to define windows over the stream then some events may not be captured in the right windows and therefore any calculations on those windows I did would be wrong What would happen if we had 10,000 events with the same StartTime? I would enqueue them with StartTime + n ticks. Along comes a genuine event with a StartTime of the very first event + 1 tick. It is now too far in the past as far as my stream is concerned and it would be dropped. Not what I would want to do at all. I decided then to look at the Timer based solution I created a timer on my input adapter that elapsed every 200ms. private Timer tmr; public SimpleInputAdapter(SimpleInputConfig configInfo) { ctx = new SimpleTimeExtractDataContext(configInfo.ConnectionString); this.configInfo = configInfo; tmr = new Timer(200); tmr.Elapsed += new ElapsedEventHandler(t_Elapsed); tmr.Enabled = true; } void t_Elapsed(object sender, ElapsedEventArgs e) { ts = DateTime.Now - dtCtiIssued; if (ts.TotalMilliseconds >= 200 && TimerIssuedCti == false) { EnqueueCtiEvent(System.DateTime.Now.AddTicks(-100)); TimerIssuedCti = true; } }   In the t_Elapsed event handler I find out the difference in time between now and when the last event was processed (dtCtiIssued). I then check to see if that is greater than or equal to 200ms and if the last issuing of a Cti was done by the timer or by a genuine event (TimerIssuedCti). If I didn’t do this check then I would enqueue a Cti every time the timer elapsed which is not something I wanted. If the difference between the two times is greater than or equal to 500ms and the last event enqueued was by a real event then I issue a Cti through the timer to flush the event Queue, otherwise I do nothing. When I enqueue the Ctis into my stream in my ProduceEvents method I also set the values of dtCtiIssued and TimerIssuedCti   currEvent = CreateInsertEvent(); currEvent.StartTime = (DateTimeOffset)dt.c2; TimerIssuedCti = false; dtCtiIssued = currEvent.StartTime; If I go ahead and run this configuration I see the following in my output. As we can see the first Cti gets enqueued as before but then another is enqueued by the timer and because this has a later timestamp it flushes the enqueued events through the engine. Conclusion Hopefully this has shown how the enqueuing of Ctis can have a dramatic effect on the responsiveness of your output in StreamInsight. Understanding the temporal nature of the product is for me one of the most important things you can learn. I have attached my solution for the demos. It is all in one project and testing each variation is a simple matter of commenting and un-commenting the parts in the code we have been dealing with here.

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• NRF Online Merchandising Workshop: Where Online Retailers Are Focusing for Holiday and Beyond

  - by Rose Spicer-Oracle

  0 0 1 1204 6863 Oracle Corporation 57 16 8051 14.0 Normal 0 false false false EN-US JA 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-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Last month we attended the NRF Online Merchandising Workshop in LA, and it was a great opportunity to catch up with our customers, meet new retailers, and hear some great presentations from VF Corporation, Zazzle, Julep Beauty, Backcountry, eBags and more. The one-on-one conversations with Merchants and the keynote presentations carry the same themes across companies of all sizes and across verticals. With only 125 days left (and counting) until Black Friday, these conversations provided some great insight in to what’s top of mind for retailers during the most stressful time of their year, and a sneak peek in to what they will deliver this holiday season.  Some of the most popular topics were: When to start promoting for holiday: seems like a funny conversation to have in July, but a number of retailers said they already had their holiday shopping gift guides live on their site, and it was attracting a significant portion of their onsite traffic. When it comes to timing, most retailers were questioning when to begin their holiday promotions -- carefully balancing when to release pricing and specials, and knowing that customers are holding out for last-minute deals and price drops. Many retailers noted the frustrations around transparent pricing by Amazon and a few other mega-retailers last year, publishing their “lowest prices of the season” as early as October – ensuring shoppers that those prices were the best they could get all season long. Many retailers felt their hands were forced to drop prices. Others kept their set pricing with negative customer reaction, causing some to miss their holiday goals. The pressure is on, and most retailers identified November 1 as their target start date for the holiday promotions blitz. Some are even waiting for the big guys to release their “lowest prices of the season” guides and will then follow suit.      Attribution is tough – and a huge focus: understanding the path to conversion is a tough nut to crack, especially in the new omnichannel world where consumers use multiple touchpoints to make a single purchase, and internal management wants to know hard data. This has lead many retailers to invest in attribution; carefully tracking their online marketing efforts to determine what gets “credit” for the sale, instead of giving credit to the “last click.” Retailers noted that it is very difficult to determine the numbers when online and offline worlds collide – like when a shopper uses digital channels for research and then makes a purchase in a store. As one of the presenters from The North Face mentioned in her keynote, a key to enabling better customer service and satisfaction when it comes to converged online and offline sales is training the in-store staff, and creating a culture where it eventually “doesn’t matter what group gets the credit” if they all add to the sale. No doubt, the area of attribution will be a big area of retail investment in the coming years.      How to plan for the converged world: planning to ensure inventory gets where it needs to be was another concern. In conversations with retailers, we advised them to analyze customer patterns: where shoppers purchase items, where the items were sourced from and even where items are returned. This analysis is very valuable in determining inventory plans. From there, retailers can more accurately plan and allocate inventory to support both the online and offline customer behavior. As we head into the holiday season, the need for accurate enterprise-wide inventory visibility, and providing that information to associates, is even more critical to the brand-wide customer experience.       Improving the search / navigation / usability of the site(s): Aside from some of the big ideas and standard holiday pricing pressure, most conversations we had centered around continuing to improve the basics of the site. Reinvesting in search and navigation came up time and time again (FitForCommerce blogged about what a big topic it was at the event as well). Obviously getting shoppers on their path quickly and allowing them to find what they need fast is critical, but it was definitely interesting to hear just how much effort is still going in to honing the search and navigation experience. Adding new elements to search and navigation like typeahed, inventive navigation refinements, and new navigation categories like gift guides, specialized boutiques and flash sales were top of mind, in addition to searchandising and making search-driven product recommendations. (Oracle can help!)       Reducing cart abandonment: always a hot topic that is top of mind for every online retailer. Getting shoppers to the cart is often less then half the battle; getting them to click “buy” and complete the transaction is much more difficult. While retailers carefully study the checkout process and where shoppers tend to bounce, they know that how they design their checkout page is critical. We’re all online shoppers in our personal lives and we know how frustrating it can be when total prices are not transparent (i.e. shipping, processing, taxes is not included until the very last possible screen before clicking that buy button). Online retailers are struggling with where in the checkout process to surface the total price to be charged to reduce cart abandonment, while not showing the total figure too early in the process that it keeps shoppers from getting to checkout altogether. Recent research shows that providing total pricing prior to the checkout process dramatically reduces cart abandonment – as it serves as a filter to those shopping within a specific price band. Much of the cart abandonment discussion leads us to…       The free shipping / free returns question: it’s no secret that because of Amazon and programs like Prime, consumers expect free shipping, much to the chagrin of the smaller retailer. The reality is that if you’re not a mega-retailer, shipping is an expensive part of doing business that doesn’t allow most retailers to keep their prices low and offer free shipping. This has many retailers venturing out on the “free returns” path, especially in apparel. A number of retailers we spoke with are testing a flat rate shipping fee with free returns to see if they can crack the price threshold where shoppers are willing to pay for shipping with an added service. But, free shipping remains king.      Social ads and retargeting: they are working, but do they turn off consumers? That’s the big question. Every retailer we spoke with during a roundtable on the topic said that social ads and retargeting (where that pair of boots you’re been eyeing on a site magically follows you around the Internet) work and are meeting campaign goals. The larger question many retailers are asking is if this type of tactic is turning off a large number of shoppers, even if these campaigns are meeting their early goals. Retailers also mentioned that Facebook ads are working very well for them, especially when it comes to new customer acquisition, serving as a complimentary a channel to SEO when it comes to engaging new customers. While there are always new things to experiment with in retail, standard challenges are top of mind as retailers scramble to get ready for holiday. It will undoubtedly be another record-breaking online shopping season, but as retailers get more and more advanced with each Black Friday, expect some exciting things. This excitement needs to be backed by sound solutions and optimized operations. Then again, consumers are expecting more than ever, so I don’t doubt that retailers are already thinking about the possibilities of holiday 2015… and beyond. Customers who read this article, also found value in the following stories: Personalization for Retail: http://blogs.oracle.com/retail/entry/personalization_for_retailShop Direct User Experience Focus Drives Sales:https://blogs.oracle.com/retail/entry/shop_direct_user_experience_focusMaking Waves: Australian Online Retailer SurfStitch: https://blogs.oracle.com/oracleretail/entry/surf_stitchWhat’s new in Oracle Commerce v11.1 for RetailWhat the Content+Commerce Equation is Missing

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• Following the Thread in OSB

  - by Antony Reynolds

  Threading in OSB The Scenario I recently led an OSB POC where we needed to get high throughput from an OSB pipeline that had the following logic: 1. Receive Request 2. Send Request to External System 3. If Response has a particular value   3.1 Modify Request   3.2 Resend Request to External System 4. Send Response back to Requestor All looks very straightforward and no nasty wrinkles along the way.  The flow was implemented in OSB as follows (see diagram for more details): Proxy Service to Receive Request and Send Response Request Pipeline   Copies Original Request for use in step 3 Route Node   Sends Request to External System exposed as a Business Service Response Pipeline   Checks Response to Check If Request Needs to Be Resubmitted Modify Request Callout to External System (same Business Service as Route Node) The Proxy and the Business Service were each assigned their own Work Manager, effectively giving each of them their own thread pool. The Surprise Imagine our surprise when, on stressing the system we saw it lock up, with large numbers of blocked threads.  The reason for the lock up is due to some subtleties in the OSB thread model which is the topic of this post.   Basic Thread Model OSB goes to great lengths to avoid holding on to threads.  Lets start by looking at how how OSB deals with a simple request/response routing to a business service in a route node. Most Business Services are implemented by OSB in two parts.  The first part uses the request thread to send the request to the target.  In the diagram this is represented by the thread T1.  After sending the request to the target (the Business Service in our diagram) the request thread is released back to whatever pool it came from.  A multiplexor (muxer) is used to wait for the response.  When the response is received the muxer hands off the response to a new thread that is used to execute the response pipeline, this is represented in the diagram by T2. OSB allows you to assign different Work Managers and hence different thread pools to each Proxy Service and Business Service.  In out example we have the “Proxy Service Work Manager” assigned to the Proxy Service and the “Business Service Work Manager” assigned to the Business Service.  Note that the Business Service Work Manager is only used to assign the thread to process the response, it is never used to process the request. This architecture means that while waiting for a response from a business service there are no threads in use, which makes for better scalability in terms of thread usage. First Wrinkle Note that if the Proxy and the Business Service both use the same Work Manager then there is potential for starvation.  For example: Request Pipeline makes a blocking callout, say to perform a database read. Business Service response tries to allocate a thread from thread pool but all threads are blocked in the database read. New requests arrive and contend with responses arriving for the available threads. Similar problems can occur if the response pipeline blocks for some reason, maybe a database update for example. Solution The solution to this is to make sure that the Proxy and Business Service use different Work Managers so that they do not contend with each other for threads. Do Nothing Route Thread Model So what happens if there is no route node?  In this case OSB just echoes the Request message as a Response message, but what happens to the threads?  OSB still uses a separate thread for the response, but in this case the Work Manager used is the Default Work Manager. So this is really a special case of the Basic Thread Model discussed above, except that the response pipeline will always execute on the Default Work Manager.   Proxy Chaining Thread Model So what happens when the route node is actually calling a Proxy Service rather than a Business Service, does the second Proxy Service use its own Thread or does it re-use the thread of the original Request Pipeline? Well as you can see from the diagram when a route node calls another proxy service then the original Work Manager is used for both request pipelines.  Similarly the response pipeline uses the Work Manager associated with the ultimate Business Service invoked via a Route Node.  This actually fits in with the earlier description I gave about Business Services and by extension Route Nodes they “… uses the request thread to send the request to the target”. Call Out Threading Model So what happens when you make a Service Callout to a Business Service from within a pipeline.  The documentation says that “The pipeline processor will block the thread until the response arrives asynchronously” when using a Service Callout.  What this means is that the target Business Service is called using the pipeline thread but the response is also handled by the pipeline thread.  This implies that the pipeline thread blocks waiting for a response.  It is the handling of this response that behaves in an unexpected way. When a Business Service is called via a Service Callout, the calling thread is suspended after sending the request, but unlike the Route Node case the thread is not released, it waits for the response.  The muxer uses the Business Service Work Manager to allocate a thread to process the response, but in this case processing the response means getting the response and notifying the blocked pipeline thread that the response is available.  The original pipeline thread can then continue to process the response. Second Wrinkle This leads to an unfortunate wrinkle.  If the Business Service is using the same Work Manager as the Pipeline then it is possible for starvation or a deadlock to occur.  The scenario is as follows: Pipeline makes a Callout and the thread is suspended but still allocated Multiple Pipeline instances using the same Work Manager are in this state (common for a system under load) Response comes back but all Work Manager threads are allocated to blocked pipelines. Response cannot be processed and so pipeline threads never unblock – deadlock! Solution The solution to this is to make sure that any Business Services used by a Callout in a pipeline use a different Work Manager to the pipeline itself. The Solution to My Problem Looking back at my original workflow we see that the same Business Service is called twice, once in a Routing Node and once in a Response Pipeline Callout.  This was what was causing my problem because the response pipeline was using the Business Service Work Manager, but the Service Callout wanted to use the same Work Manager to handle the responses and so eventually my Response Pipeline hogged all the available threads so no responses could be processed. The solution was to create a second Business Service pointing to the same location as the original Business Service, the only difference was to assign a different Work Manager to this Business Service.  This ensured that when the Service Callout completed there were always threads available to process the response because the response processing from the Service Callout had its own dedicated Work Manager. Summary Request Pipeline Executes on Proxy Work Manager (WM) Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Route Node Request sent using Proxy WM Thread Proxy WM Thread is released before getting response Muxer is used to handle response Muxer hands off response to Business Service (BS) WM Response Pipeline Executes on Routed Business Service WM Thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. No Route Node (Echo functionality) Proxy WM thread released New thread from the default WM used for response pipeline Service Callout Request sent using proxy pipeline thread Proxy thread is suspended (not released) until the response comes back Notification of response handled by BS WM thread so limited by setting of that WM.  If no WM specified then uses WLS default WM. Note this is a very short lived use of the thread After notification by callout BS WM thread that thread is released and execution continues on the original pipeline thread. Route/Callout to Proxy Service Request Pipeline of callee executes on requestor thread Response Pipeline of caller executes on response thread of requested proxy Throttling Request message may be queued if limit reached. Requesting thread is released (route node) or suspended (callout) So what this means is that you may get deadlocks caused by thread starvation if you use the same thread pool for the business service in a route node and the business service in a callout from the response pipeline because the callout will need a notification thread from the same thread pool as the response pipeline.  This was the problem we were having. You get a similar problem if you use the same work manager for the proxy request pipeline and a business service callout from that request pipeline. It also means you may want to have different work managers for the proxy and business service in the route node. Basically you need to think carefully about how threading impacts your proxy services. References Thanks to Jay Kasi, Gerald Nunn and Deb Ayers for helping to explain this to me.  Any errors are my own and not theirs.  Also thanks to my colleagues Milind Pandit and Prasad Bopardikar who travelled this road with me. OSB Thread Model Great Blog Post on Thread Usage in OSB

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• Book Review - Programming Windows Azure by Siriram Krishnan

  - by BuckWoody

  As part of my professional development, I’ve created a list of books to read throughout the year, starting in June of 2011. This a review of the first one, called Programming Windows Azure by Siriram Krishnan. You can find my entire list of books I’m reading for my career here: http://blogs.msdn.com/b/buckwoody/archive/2011/06/07/head-in-the-clouds-eyes-on-the-books.aspx  Why I Chose This Book: As part of my learning style, I try to read multiple books about a single subject. I’ve found that at least 3 books are necessary to get the right amount of information to me. This is a “technical” work, meaning that it deals with technology and not business, writing or other facets of my career. I’ll have a mix of all of those as I read along. I chose this work in addition to others I’ve read since it covers everything from an introduction to more advanced topics in a single book. It also has some practical examples of actually working with the product, particularly on storage. Although it’s dated, many examples normally translate. I also saw that it had pretty good reviews. What I learned: I learned a great deal about storage, and many useful code snippets. I do think that there could have been more of a focus on the application fabric - but of course that wasn’t as mature a feature when this book was written. I learned some great architecture examples, and in one section I learned more about encryption. In that example, however, I would rather have seen the examples go the other way - the book focused on moving data from on-premise to Azure storage in an encrypted fashion. Using the Application Fabric I would rather see sensitive data left in a hybrid fashion on premise, and connect to for the Azure application. Even so, the examples were very useful. If you’re looking for a good “starter” Azure book, this is a good choice. I also recommend the last chapter as a quick read for a DBA, or Database Administrator. It’s not very long, but useful. Note that the limits described are incorrect - which is one of the dangers of reading a book about any cloud offering. The services offered are updated so quickly that the information is in constant danger of being “stale”. Even so, I found this a useful book, which I believe will help me work with Azure better. Raw Notes: I take notes as I read, calling that process “reading with a pencil”. I find that when I do that I pay attention better, and record some things that I need to know later. I’ll take these notes, categorize them into a OneNote notebook that I synchronize in my Live.com account, and that way I can search them from anywhere. I can even read them on the web, since the Live.com has a OneNote program built in. Note that these are the raw notes, so they might not make a lot of sense out of context - I include them here so you can watch my though process. Programming Windows Azure by Siriram Krishnan: Learning about how to select applications suitable for Distributed Technology. Application Fabric gets the least attention; probably because it was newer at the time. Very clear (Chapter One) Good foundation Background and history, but not too much I normally arrange my descriptions differently, starting with the use-cases and moving to physicality, but this difference helps me. Interesting that I am reading this using Safari Books Online, which uses many of these concepts. Taught me some new aspects of a Hypervisor – very low-level information about the Azure Fabric (not to be confused with the Application Fabric feature) (Chapter Two) Good detail of what is included in the SDK. Even more is available now. CS = Cloud Service (Chapter 3) Place Storage info in the configuration file, since it can be streamed in-line with a running app. Ditto for logging, and keep separated configs for staging and testing. Easy-switch in and switch out.  (Chapter 4) There are two Runtime API’s, one of external and one for internal. Realizing how powerful this paradigm really is. Some places seem light, and to drop off but perhaps that’s best. Managing API is not charged, which is nice. I don’t often think about the price, until it comes to an actual deployment (Chapter 5) Csmanage is something I want to dig into deeper. API requires package moves to Blob storage first, so it needs a URL. Csmanage equivalent can be written in Unix scripting using openssl. Upgrades are possible, and you use the upgradeDomainCount attribute in the Service-Definition.csdef file  Always use a low-privileged account to test on the dev fabric, since Windows Azure runs in partial trust. Full trust is available, but can be dangerous and must be well-thought out. (Chapter 6) Learned how to run full CMD commands in a web window – not that you would ever do that, but it was an interesting view into those links. This leads to a discussion on hosting other runtimes (such as Java or PHP) in Windows Azure. I got an expanded view on this process, although this is where the book shows its age a little. Books can be a problem for Cloud Computing for this reason – things just change too quickly. Windows Azure storage is not eventually consistent – it is instantly consistent with multi-phase commit. Plumbing for this is internal, not required to code that. (Chapter 7) REST API makes the service interoperable, hybrid, and consistent across code architectures. Nicely done. Use affinity groups to keep data and code together. Side note: e-book readers need a common “notes” feature. There’s a decent quick description of REST in this chapter. Learned about CloudDrive code – PowerShell sample that mounts Blob storage as a local provider. Works against Dev fabric by default, can be switched to Account. Good treatment in the storage chapters on the differences between using Dev storage and Azure storage. These can be mitigated. No, blobs are not of any size or number. Not a good statement (Chapter 8) Blob storage is probably Azure’s closest play to Infrastructure as a Service (Iaas). Blob change operations must be authenticated, even when public. Chapters on storage are pretty in-depth. Queue Messages are base-64 encoded (Chapter 9) The visibility timeout ensures processing of message in a disconnected system. Order is not guaranteed for a message, so if you need that set an increasing number in the queue mechanism. While Queues are accessible via REST, they are not public and are secured by default. Interesting – the header for a queue request includes an estimated count. This can be useful to create more worker roles in a dynamic system. Each Entity (row) in the Azure Table service is atomic – all or nothing. (Chapter 10) An entity can have up to 255 Properties  Use “ID” for the class to indicate the key value, or use the [DataServiceKey] Attribute.  LINQ makes working with the Azure Table Service much easier, although Interop is certainly possible. Good description on the process of selecting the Partition and Row Key.  When checking for continuation tokens for pagination, include logic that falls out of the check in case you are at the last page.  On deleting a storage object, it is instantly unavailable, however a background process is dispatched to perform the physical deletion. So if you want to re-create a storage object with the same name, add retry logic into the code. Interesting approach to deleting an index entity without having to read it first – create a local entity with the same keys and apply it to the Azure system regardless of change-state.  Although the “Indexes” description is a little vague, it’s interesting to see a Folding and Stemming discussion a-la the Porter Stemming Algorithm. (Chapter 11)  Presents a better discussion of indexes (at least inverted indexes) later in the chapter. Great treatment for DBA’s in Chapter 11. We need to work on getting secondary indexes in Table storage. There is a limited form of transactions called “Entity Group Transactions” that, although they have conditions, makes a transactional system more possible. Concurrency also becomes an issue, but is handled well if you’re using Data Services in .NET. It watches the Etag and allows you to take action appropriately. I do not recommend using Azure as a location for secure backups. In fact, I would rather have seen the examples in (Chapter 12) go the other way, showing how data could be brought back to a local store as a DR or HA strategy. Good information on cryptography and so on even so. Chapter seems out of place, and should be combined with the Blob chapter.  (Chapter 13) on SQL Azure is dated, although the base concepts are OK.  Nice example of simple ADO.NET access to a SQL Azure (or any SQL Server Really) database.  

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• Refactor This (Ugly Code)!

  - by Alois Kraus

  Ayende has put on his blog some ugly code to refactor. First and foremost it is nearly impossible to reason about other peoples code without knowing the driving forces behind the current code. It is certainly possible to make it much cleaner when potential sources of errors cannot happen in the first place due to good design. I can see what the intention of the code is but I do not know about every brittle detail if I am allowed to reorder things here and there to simplify things. So I decided to make it much simpler by identifying the different responsibilities of the methods and encapsulate it in different classes. The code we need to refactor seems to deal with a handler after a message has been sent to a message queue. The handler does complete the current transaction if there is any and does handle any errors happening there. If during the the completion of the transaction errors occur the transaction is at least disposed. We can enter the handler already in a faulty state where we try to deliver the complete event in any case and signal a failure event and try to resend the message again to the queue if it was not inside a transaction. All is decorated with many try/catch blocks, duplicated code and some state variables to route the program flow. It is hard to understand and difficult to reason about. In other words: This code is a mess and could be written by me if I was under pressure. Here comes to code we want to refactor:         private void HandleMessageCompletion(                                      Message message,                                      TransactionScope tx,                                      OpenedQueue messageQueue,                                      Exception exception,                                      Action<CurrentMessageInformation, Exception> messageCompleted,                                      Action<CurrentMessageInformation> beforeTransactionCommit)         {             var txDisposed = false;             if (exception == null)             {                 try                 {                     if (tx != null)                     {                         if (beforeTransactionCommit != null)                             beforeTransactionCommit(currentMessageInformation);                         tx.Complete();                         tx.Dispose();                         txDisposed = true;                     }                     try                     {                         if (messageCompleted != null)                             messageCompleted(currentMessageInformation, exception);                     }                     catch (Exception e)                     {                         Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e);                     }                     return;                 }                 catch (Exception e)                 {                     Trace.TraceWarning("Failed to complete transaction, moving to error mode"+ e);                     exception = e;                 }             }             try             {                 if (txDisposed == false && tx != null)                 {                     Trace.TraceWarning("Disposing transaction in error mode");                     tx.Dispose();                 }             }             catch (Exception e)             {                 Trace.TraceWarning("Failed to dispose of transaction in error mode."+ e);             }             if (message == null)                 return;                 try             {                 if (messageCompleted != null)                     messageCompleted(currentMessageInformation, exception);             }             catch (Exception e)             {                 Trace.TraceError("An error occured when raising the MessageCompleted event, the error will NOT affect the message processing"+ e);             }               try             {                 var copy = MessageProcessingFailure;                 if (copy != null)                     copy(currentMessageInformation, exception);             }             catch (Exception moduleException)             {                 Trace.TraceError("Module failed to process message failure: " + exception.Message+                                              moduleException);             }               if (messageQueue.IsTransactional == false)// put the item back in the queue             {                 messageQueue.Send(message);             }         }     You can see quite some processing and handling going on there. Yes this looks like real world code one did put together to make things work and he does not trust his callbacks. I guess these are event handlers which are optional and the delegates were extracted from an event to call them back later when necessary.  Lets see what the author of this code did intend:          private void HandleMessageCompletion(             TransactionHandler transactionHandler,             MessageCompletionHandler handler,             CurrentMessageInformation messageInfo,             ErrorCollector errors             )         {               // commit current pending transaction             transactionHandler.CallHandlerAndCommit(messageInfo, errors);               // We have an error for a null message do not send completion event             if (messageInfo.CurrentMessage == null)                 return;               // Send completion event in any case regardless of errors             handler.OnMessageCompleted(messageInfo, errors);               // put message back if queue is not transactional             transactionHandler.ResendMessageOnError(messageInfo.CurrentMessage, errors);         }   I did not bother to write the intention here again since the code should be pretty self explaining by now. I have used comments to explain the still nontrivial procedure step by step revealing the real intention about all this complex program flow. The original complexity of the problem domain does not go away but by applying the techniques of SRP (Single Responsibility Principle) and some functional style but we can abstract the necessary complexity away in useful abstractions which make it much easier to reason about it. Since most of the method seems to deal with errors I thought it was a good idea to encapsulate the error state of our current message in an ErrorCollector object which stores all exceptions in a list along with a description what the error all was about in the exception itself. We can log it later or not depending on the log level or whatever. It is really just a simple list that encapsulates the current error state.          class ErrorCollector          {              List<Exception> _Errors = new List<Exception>();                public void Add(Exception ex, string description)              {                  ex.Data["Description"] = description;                  _Errors.Add(ex);              }                public Exception Last              {                  get                  {                      return _Errors.LastOrDefault();                  }              }                public bool HasError              {                  get                  {                      return _Errors.Count > 0;                  }              }          }   Since the error state is global we have two choices to store a reference in the other helper objects (TransactionHandler and MessageCompletionHandler)or pass it to the method calls when necessary. I did chose the latter one because a second argument does not hurt and makes it easier to reason about the overall state while the helper objects remain stateless and immutable which makes the helper objects much easier to understand and as a bonus thread safe as well. This does not mean that the stored member variables are stateless or thread safe as well but at least our helper classes are it. Most of the complexity is located the transaction handling I consider as a separate responsibility that I delegate to the TransactionHandler which does nothing if there is no transaction or Call the Before Commit Handler Commit Transaction Dispose Transaction if commit did throw In fact it has a second responsibility to resend the message if the transaction did fail. I did see a good fit there since it deals with transaction failures.          class TransactionHandler          {              TransactionScope _Tx;              Action<CurrentMessageInformation> _BeforeCommit;              OpenedQueue _MessageQueue;                public TransactionHandler(TransactionScope tx, Action<CurrentMessageInformation> beforeCommit, OpenedQueue messageQueue)              {                  _Tx = tx;                  _BeforeCommit = beforeCommit;                  _MessageQueue = messageQueue;              }                public void CallHandlerAndCommit(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  if (_Tx != null && !errors.HasError)                  {                      try                      {                          if (_BeforeCommit != null)                          {                              _BeforeCommit(currentMessageInfo);                          }                            _Tx.Complete();                          _Tx.Dispose();                      }                      catch (Exception ex)                      {                          errors.Add(ex, "Failed to complete transaction, moving to error mode");                          Trace.TraceWarning("Disposing transaction in error mode");                          try                          {                              _Tx.Dispose();                          }                          catch (Exception ex2)                          {                              errors.Add(ex2, "Failed to dispose of transaction in error mode.");                          }                      }                  }              }                public void ResendMessageOnError(Message message, ErrorCollector errors)              {                  if (errors.HasError && !_MessageQueue.IsTransactional)                  {                      _MessageQueue.Send(message);                  }              }          } If we need to change the handling in the future we have a much easier time to reason about our application flow than before. After we did complete our transaction and called our callback we can call the completion handler which is the main purpose of the HandleMessageCompletion method after all. The responsiblity o the MessageCompletionHandler is to call the completion callback and the failure callback when some error has occurred.            class MessageCompletionHandler          {              Action<CurrentMessageInformation, Exception> _MessageCompletedHandler;              Action<CurrentMessageInformation, Exception> _MessageProcessingFailure;                public MessageCompletionHandler(Action<CurrentMessageInformation, Exception> messageCompletedHandler,                                              Action<CurrentMessageInformation, Exception> messageProcessingFailure)              {                  _MessageCompletedHandler = messageCompletedHandler;                  _MessageProcessingFailure = messageProcessingFailure;              }                  public void OnMessageCompleted(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  try                  {                      if (_MessageCompletedHandler != null)                      {                          _MessageCompletedHandler(currentMessageInfo, errors.Last);                      }                  }                  catch (Exception ex)                  {                      errors.Add(ex, "An error occured when raising the MessageCompleted event, the error will NOT affect the message processing");                  }                    if (errors.HasError)                  {                      SignalFailedMessage(currentMessageInfo, errors);                  }              }                void SignalFailedMessage(CurrentMessageInformation currentMessageInfo, ErrorCollector errors)              {                  try                  {                      if (_MessageProcessingFailure != null)                          _MessageProcessingFailure(currentMessageInfo, errors.Last);                  }                  catch (Exception moduleException)                  {                      errors.Add(moduleException, "Module failed to process message failure");                  }              }            }   If for some reason I did screw up the logic and we need to call the completion handler from our Transaction handler we can simple add to the CallHandlerAndCommit method a third argument to the MessageCompletionHandler and we are fine again. If the logic becomes even more complex and we need to ensure that the completed event is triggered only once we have now one place the completion handler to capture the state. During this refactoring I simple put things together that belong together and came up with useful abstractions. If you look at the original argument list of the HandleMessageCompletion method I have put many things together:   Original Arguments New Arguments Encapsulate Message message CurrentMessageInformation messageInfo         Message message TransactionScope tx Action<CurrentMessageInformation> beforeTransactionCommit OpenedQueue messageQueue TransactionHandler transactionHandler        TransactionScope tx        OpenedQueue messageQueue        Action<CurrentMessageInformation> beforeTransactionCommit Exception exception,             ErrorCollector errors Action<CurrentMessageInformation, Exception> messageCompleted MessageCompletionHandler handler          Action<CurrentMessageInformation, Exception> messageCompleted          Action<CurrentMessageInformation, Exception> messageProcessingFailure The reason is simple: Put the things that have relationships together and you will find nearly automatically useful abstractions. I hope this makes sense to you. If you see a way to make it even more simple you can show Ayende your improved version as well.

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• CodePlex Daily Summary for Wednesday, September 26, 2012

  CodePlex Daily Summary for Wednesday, September 26, 2012Popular ReleasesThe Eggbert Chronicles: Eggbert Chronicles v1: Version 1 of Eggbert Chronicles. Includes: Basic Menu System Fully-Functional Options Menu (need to auto-adjust adv. settings when preset is changed) Basic First Level (It's pre-alpha, level design isn't a must, gameplay mechanics first) 2D Movement System in a 3D World (2.5D Basically) Planned: An actual playermodel Actual custom texturing Platformer Objects: Spikes Sawblades Basic Enemies (Most likely x-axis movement) Tar pits Acid pits More puzzles Custom sound effect...D3 Loot Tracker: 1.3.1 (patch): - Magic find value will now display properly and includes follower value. - ILevel of legendary items will now display properly.WinRtBehaviors: V1.0.2: Includes simple Blend SupportMVC Bootstrap: MVC Boostrap 0.5.1: A small demo site, based on the default ASP.NET MVC 3 project template, showing off some of the features of MVC Bootstrap. This release uses Entity Framework 5 for data access and Ninject 3 for dependency injection. If you download and use this project, please give some feedback, good or bad!Windows Powershell/Quest AD account audit and reporting: Powershell AD Reporting Framework: Alpha 0.0.1 ReleasePicturethrill: Version 2.9.25.0: Allowing to run Picturethrill Update task while computer is not connected to internet on computer wake up.VCC: Latest build, v2.3.00925.0: Automatic drop of latest buildSimple PM - Project Management Simplified !: Simple Pm v1 - Aplha (Re-released): INSTALLATION GUIDE 1. Run the web setup, which will install the web app to IIS. 2. Make sure you select your application pool to "ASP.NET v4.0" during the installation. 3. Create a database named "SimplePm" 4. Run the attached database script on this database. 5. Change the database username and password in connection strings defined as SimplePmEntities and ApplicationServices from the Web.config file 6. Thats its ! Simple Pm are ready to go ! For any installation assistance feel free to c...menu4web: menu4web 1.0 - free javascript menu for web sites: menu4web 1.0 has been tested with all major browsers: Firefox, Chrome, IE, Opera and Safari. Minified m4w.js library is less than 9K. Includes 21 menu examples of different styles. Can be freely distributed under The MIT License (MIT).Rawr: Rawr 5.0.0: This is the Downloadable WPF version of Rawr!For web-based version see http://elitistjerks.com/rawr.php You can find the version notes at: http://rawr.codeplex.com/wikipage?title=VersionNotes Rawr Addon (NOT UPDATED YET FOR MOP)We now have a Rawr Official Addon for in-game exporting and importing of character data hosted on Curse. The Addon does not perform calculations like Rawr, it simply shows your exported Rawr data in wow tooltips and lets you export your character to Rawr (including ba...Coevery - Free CRM: Coevery 1.0.0.26: The zh-CN issue has been solved. We also add a project management module.EntitiesToDTOs - Entity Framework DTO Generator: EntitiesToDTOs.v3.0.Beta.2: Support for new Entity Framework EDMX (format used by VS2012) ! Support for Enum Types! DTOs and Assemblers can be generated inside project folders! Optional automatic check for updates! Support for Visual Studio 2012 !!! Choose types you want to generate! Warning system in types to generate! Added ToEntityList() and ToDTOList() to Assemblers! Indicate class identifier for DTOs and Assemblers! Cleaner Assemblers code. Ad module to support the AddIn! Lots of fixes and imp...VidCoder: 1.4.1 Beta: Updated to HandBrake 4971. This should fix some issues with stuck PGS subtitles. Fixed build break which prevented pre-compiled XML serializers from showing up. Fixed problem where a preset would get errantly marked as modified when re-opening the encode settings window or importing a new preset.SharePoint WarmUp: Nauplius.SP.Initalization: Initial release.JSLint for Visual Studio 2010: 1.4.0: VS2012 support is alphaBlackJumboDog: Ver5.7.2: 2012.09.23 Ver5.7.2 (1)InetTest?? (2)HTTP?????????????????100???????????Player Framework by Microsoft: Player Framework for Windows 8 (Preview 6): IMPORTANT: List of breaking changes from preview 5 Added separate samples download with .vsix dependencies instead of source dependencies Support for FreeWheel SmartXML ad responses Support for Smooth Streaming SDK DownloaderPlugins Support for VMAP and TTML polling for live scenarios Support for custom smooth streaming byte stream and scheme handlers Support for new play time and position tracking plugin Added IsLiveChanged event Added AdaptivePlugin.MaxBitrate property Add...WPF Application Framework (WAF): WPF Application Framework (WAF) 2.5.0.8: Version: 2.5.0.8 (Milestone 8): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Changelog Legend: [B] Breaking change; [O] Marked member as obsolete WAF: Mark the class DataModel as serializable. InfoMan: Minor improvements. InfoMan: Add unit tests for all modules. Othe...LogicCircuit: LogicCircuit 2.12.9.20: Logic Circuit - is educational software for designing and simulating logic circuits. Intuitive graphical user interface, allows you to create unrestricted circuit hierarchy with multi bit buses, debug circuits behavior with oscilloscope, and navigate running circuits hierarchy. Changes of this versionToolbars on text note dialog are more flexible now. You can select font face, size, color, and background of text you are typing. RAM now can be initialized to one of the following: random va...SiteMap Editor for Microsoft Dynamics CRM 2011: SiteMap Editor (1.1.2020.421): New features: Disable a specific part of SiteMap to keep the data without displaying them in the CRM application. It simply comments XML part of the sitemap (thanks to rboyers for this feature request) Right click an item and click on "Disable" to disable it Items disabled are greyed and a suffix "- disabled" is added Right click an item and click on "Enable" to enable it Refresh list of web resources in the web resources pickerNew Projectsaftermath: Provides sse/avx implementation for matrix storage, access and basic operations, probability distributions and fast ziggurat random number generators.Agility: Agility is a management tool for the agile enterprise. It supports encourages ussage of agile methodology from portfolio and management to development.ASP.NET WebForm MVVM: MVVM for ASP.NET WebFormsAzugBeDemo: some text hereBookmark Browser: Web application that allows access to your Firefox Sync bookmarks on platforms that are not supported by Firefox (e.g. iOS).Cachalote-Todo-WPF-Skins: These are skin projects for Cachalote Todo WPF project.CodePlexDeployment01: Project set up to demonstrate codeplex deploymentColorChooser X2: comming soon...De Todo Un Poco: de todo un pcoDeals Patrol: Deals patrolEasy IP Changer: Wechseln von IP Adressen pro AdapterEasyStock: EasyStock is a small and easy to use Windows 8 app that gives you an overview of your favorite stocks with historical data for the last days, months and years. Find++: Find++ finds specific string in multiple files in a folderGoShunn: A DotNetNuke ModuleJquery DataTables Plugin c#, .NET, MS SQL Server and Webservices Example: A working example of JQuery DataTables in C#, ASP.NET, SQL Server side processing with ajax and webservices.Keywords Translator (MUI helper): MUI helper for translate words in others languages.Mupen: A Nentendo 64 Emulator. This emulator is based on the Mupen64plus code, and made to be used for learning purposes.NFC Card Demo: ??nfc?，???demo,???roboguice ioc??NJection.LambdaConverter: NJection.LambdaConverter is an assembly for converting delegates resolved from methods/constructors to expression trees. Copyright 2009-2012 Sagi FogelQuickPasteIt: QuickPasteIt is a pastebin tool for Windows and Visual Studio (2010 & 2012) which makes sharing code files and snippets as easy as one click.SharePoint Move Discussion Threads: SharePoint Move Discussion Threads solution is a tool that allows to move a thread across discussion boards within a site-collection.SQL LocalDB Wrapper: SQL LocalDB Wrapper is a .NET 3.5 assembly providing interop with the SQL LocalDB native API from managed code using .NET APIs.Study Time: Windows 8 metro style app. Create Quizzes and study card. Use the study cards either in the Windows 8 app or WP7 Companion App. Use Skydrive for storage.TenterTaobaoke: toatoaoke projaecttestddgit09252012: stestddhg0925201201: sTrigger: A DotNetNuke C# ModuleUML Creator: This is a programmering project made by 4 students from the Technical University of Denmark, and is a part of the course Windows Programming C# and .NET.W8 Ateneo Libri: No summaryWDSS-II MergedDataViewer: Quickly view merged variables map produced from w2merger Webshop for Orchard: This is Ecommerce Module to Orchard based on SkyWalker's excellent serial blogsWindows Powershell/Quest AD account audit and reporting: Powershell framework utilizing Quest Active Directory commandlet for the generation of user account, group membership and access audit reports.WinRT.Toolkit: I'm trying to Build a Charting Control Set for Windows 8 Modern UI I already Built a Pie Chart which is available now on http://blogs.msdn.com/b/mertoappsXades Library: Xades Library, currently with Xades-T capabilities and compatible with eHealth and MyCareNet.

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• C#: Why Decorate When You Can Intercept

  - by James Michael Hare

  We've all heard of the old Decorator Design Pattern (here) or used it at one time or another either directly or indirectly.  A decorator is a class that wraps a given abstract class or interface and presents the same (or a superset) public interface but "decorated" with additional functionality.   As a really simplistic example, consider the System.IO.BufferedStream, it itself is a descendent of System.IO.Stream and wraps the given stream with buffering logic while still presenting System.IO.Stream's public interface:   1: Stream buffStream = new BufferedStream(rawStream); Now, let's take a look at a custom-code example.  Let's say that we have a class in our data access layer that retrieves a list of products from a database:  1: // a class that handles our CRUD operations for products 2: public class ProductDao 3: { 4: ... 5:  6: // a method that would retrieve all available products 7: public IEnumerable<Product> GetAvailableProducts() 8: { 9: var results = new List<Product>(); 10:  11: // must create the connection 12: using (var con = _factory.CreateConnection()) 13: { 14: con.ConnectionString = _productsConnectionString; 15: con.Open(); 16:  17: // create the command 18: using (var cmd = _factory.CreateCommand()) 19: { 20: cmd.Connection = con; 21: cmd.CommandText = _getAllProductsStoredProc; 22: cmd.CommandType = CommandType.StoredProcedure; 23:  24: // get a reader and pass back all results 25: using (var reader = cmd.ExecuteReader()) 26: { 27: while(reader.Read()) 28: { 29: results.Add(new Product 30: { 31: Name = reader["product_name"].ToString(), 32: ... 33: }); 34: } 35: } 36: } 37: }            38:  39: return results; 40: } 41: } Yes, you could use EF or any myriad other choices for this sort of thing, but the germaine point is that you have some operation that takes a non-trivial amount of time.  What if, during the production day I notice that my application is performing slowly and I want to see how much of that slowness is in the query versus my code.  Well, I could easily wrap the logic block in a System.Diagnostics.Stopwatch and log the results to log4net or other logging flavor of choice: 1:     // a class that handles our CRUD operations for products 2:     public class ProductDao 3:     { 4:         private static readonly ILog _log = LogManager.GetLogger(typeof(ProductDao)); 5:         ... 6:         7:         // a method that would retrieve all available products 8:         public IEnumerable<Product> GetAvailableProducts() 9:         { 10:             var results = new List<Product>(); 11:             var timer = Stopwatch.StartNew(); 12:             13:             // must create the connection 14:             using (var con = _factory.CreateConnection()) 15:             { 16:                 con.ConnectionString = _productsConnectionString; 17:                 18:                 // and all that other DB code... 19:                 ... 20:             } 21:             22:             timer.Stop(); 23:             24:             if (timer.ElapsedMilliseconds > 5000) 25:             { 26:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 27:                     timer.ElapsedMillseconds); 28:             } 29:             30:             return results; 31:         } 32:     } In my eye, this is very ugly.  It violates Single Responsibility Principle (SRP), which says that a class should only ever have one responsibility, where responsibility is often defined as a reason to change.  This class (and in particular this method) has two reasons to change: If the method of retrieving products changes. If the method of logging changes. Well, we could “simplify” this using the Decorator Design Pattern (here).  If we followed the pattern to the letter, we'd need to create a base decorator that implements the DAOs public interface and forwards to the wrapped instance.  So let's assume we break out the ProductDAO interface into IProductDAO using your refactoring tool of choice (Resharper is great for this). Now, ProductDao will implement IProductDao and get rid of all logging logic: 1:     public class ProductDao : IProductDao 2:     { 3:         // this reverts back to original version except for the interface added 4:     } 5:  And we create the base Decorator that also implements the interface and forwards all calls: 1:     public class ProductDaoDecorator : IProductDao 2:     { 3:         private readonly IProductDao _wrappedDao; 4:         5:         // constructor takes the dao to wrap 6:         public ProductDaoDecorator(IProductDao wrappedDao) 7:         { 8:             _wrappedDao = wrappedDao; 9:         } 10:         11:         ... 12:         13:         // and then all methods just forward their calls 14:         public IEnumerable<Product> GetAvailableProducts() 15:         { 16:             return _wrappedDao.GetAvailableProducts(); 17:         } 18:     } This defines our base decorator, then we can create decorators that add items of interest, and for any methods we don't decorate, we'll get the default behavior which just forwards the call to the wrapper in the base decorator: 1:     public class TimedThresholdProductDaoDecorator : ProductDaoDecorator 2:     { 3:         private static readonly ILog _log = LogManager.GetLogger(typeof(TimedThresholdProductDaoDecorator)); 4:         5:         public TimedThresholdProductDaoDecorator(IProductDao wrappedDao) : 6:             base(wrappedDao) 7:         { 8:         } 9:         10:         ... 11:         12:         public IEnumerable<Product> GetAvailableProducts() 13:         { 14:             var timer = Stopwatch.StartNew(); 15:             16:             var results = _wrapped.GetAvailableProducts(); 17:             18:             timer.Stop(); 19:             20:             if (timer.ElapsedMilliseconds > 5000) 21:             { 22:                 _log.WarnFormat("Long query in GetAvailableProducts() took {0} ms", 23:                     timer.ElapsedMillseconds); 24:             } 25:             26:             return results; 27:         } 28:     } Well, it's a bit better.  Now the logging is in its own class, and the database logic is in its own class.  But we've essentially multiplied the number of classes.  We now have 3 classes and one interface!  Now if you want to do that same logging decorating on all your DAOs, imagine the code bloat!  Sure, you can simplify and avoid creating the base decorator, or chuck it all and just inherit directly.  But regardless all of these have the problem of tying the logging logic into the code itself. Enter the Interceptors.  Things like this to me are a perfect example of when it's good to write an Interceptor using your class library of choice.  Sure, you could design your own perfectly generic decorator with delegates and all that, but personally I'm a big fan of Castle's Dynamic Proxy (here) which is actually used by many projects including Moq. What DynamicProxy allows you to do is intercept calls into any object by wrapping it with a proxy on the fly that intercepts the method and allows you to add functionality.  Essentially, the code would now look like this using DynamicProxy: 1: // Note: I like hiding DynamicProxy behind the scenes so users 2: // don't have to explicitly add reference to Castle's libraries. 3: public static class TimeThresholdInterceptor 4: { 5: // Our logging handle 6: private static readonly ILog _log = LogManager.GetLogger(typeof(TimeThresholdInterceptor)); 7:  8: // Handle to Castle's proxy generator 9: private static readonly ProxyGenerator _generator = new ProxyGenerator(); 10:  11: // generic form for those who prefer it 12: public static object Create<TInterface>(object target, TimeSpan threshold) 13: { 14: return Create(typeof(TInterface), target, threshold); 15: } 16:  17: // Form that uses type instead 18: public static object Create(Type interfaceType, object target, TimeSpan threshold) 19: { 20: return _generator.CreateInterfaceProxyWithTarget(interfaceType, target, 21: new TimedThreshold(threshold, level)); 22: } 23:  24: // The interceptor that is created to intercept the interface calls. 25: // Hidden as a private inner class so not exposing Castle libraries. 26: private class TimedThreshold : IInterceptor 27: { 28: // The threshold as a positive timespan that triggers a log message. 29: private readonly TimeSpan _threshold; 30:  31: // interceptor constructor 32: public TimedThreshold(TimeSpan threshold) 33: { 34: _threshold = threshold; 35: } 36:  37: // Intercept functor for each method invokation 38: public void Intercept(IInvocation invocation) 39: { 40: // time the method invocation 41: var timer = Stopwatch.StartNew(); 42:  43: // the Castle magic that tells the method to go ahead 44: invocation.Proceed(); 45:  46: timer.Stop(); 47:  48: // check if threshold is exceeded 49: if (timer.Elapsed > _threshold) 50: { 51: _log.WarnFormat("Long execution in {0} took {1} ms", 52: invocation.Method.Name, 53: timer.ElapsedMillseconds); 54: } 55: } 56: } 57: } Yes, it's a bit longer, but notice that: This class ONLY deals with logging long method calls, no DAO interface leftovers. This class can be used to time ANY class that has an interface or virtual methods. Personally, I like to wrap and hide the usage of DynamicProxy and IInterceptor so that anyone who uses this class doesn't need to know to add a Castle library reference.  As far as they are concerned, they're using my interceptor.  If I change to a new library if a better one comes along, they're insulated. Now, all we have to do to use this is to tell it to wrap our ProductDao and it does the rest: 1: // wraps a new ProductDao with a timing interceptor with a threshold of 5 seconds 2: IProductDao dao = TimeThresholdInterceptor.Create<IProductDao>(new ProductDao(), 5000); Automatic decoration of all methods!  You can even refine the proxy so that it only intercepts certain methods. This is ideal for so many things.  These are just some of the interceptors we've dreamed up and use: Log parameters and returns of methods to XML for auditing. Block invocations to methods and return default value (stubbing). Throw exception if certain methods are called (good for blocking access to deprecated methods). Log entrance and exit of a method and the duration. Log a message if a method takes more than a given time threshold to execute. Whether you use DynamicProxy or some other technology, I hope you see the benefits this adds.  Does it completely eliminate all need for the Decorator pattern?  No, there may still be cases where you want to decorate a particular class with functionality that doesn't apply to the world at large. But for all those cases where you are using Decorator to add functionality that's truly generic.  I strongly suggest you give this a try!

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• Optimizing MySQL for small VPS

  - by Chris M

  I'm trying to optimize my MySQL config for a verrry small VPS. The VPS is also running NGINX/PHP-FPM and Magento; all with a limit of 250MB of RAM. This is an output of MySQL Tuner... -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.41-3ubuntu12.8 [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in MyISAM tables: 1M (Tables: 14) [--] Data in InnoDB tables: 29M (Tables: 301) [--] Data in MEMORY tables: 1M (Tables: 17) [!!] Total fragmented tables: 301 -------- Security Recommendations ------------------------------------------- [OK] All database users have passwords assigned -------- Performance Metrics ------------------------------------------------- [--] Up for: 2d 11h 14m 58s (1M q [8.038 qps], 33K conn, TX: 2B, RX: 618M) [--] Reads / Writes: 83% / 17% [--] Total buffers: 122.0M global + 8.6M per thread (100 max threads) [!!] Maximum possible memory usage: 978.2M (404% of installed RAM) [OK] Slow queries: 0% (37/1M) [OK] Highest usage of available connections: 6% (6/100) [OK] Key buffer size / total MyISAM indexes: 32.0M/282.0K [OK] Key buffer hit rate: 99.7% (358K cached / 1K reads) [OK] Query cache efficiency: 83.4% (1M cached / 1M selects) [!!] Query cache prunes per day: 48301 [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 144K sorts) [OK] Temporary tables created on disk: 13% (27K on disk / 203K total) [OK] Thread cache hit rate: 99% (6 created / 33K connections) [!!] Table cache hit rate: 0% (32 open / 51K opened) [OK] Open file limit used: 1% (20/1K) [OK] Table locks acquired immediately: 99% (1M immediate / 1M locks) [!!] InnoDB data size / buffer pool: 29.2M/8.0M -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Reduce your overall MySQL memory footprint for system stability Enable the slow query log to troubleshoot bad queries Increase table_cache gradually to avoid file descriptor limits Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 64M) table_cache (> 32) innodb_buffer_pool_size (>= 29M) and this is the config. # # The MySQL database server configuration file. # # You can copy this to one of: # - "/etc/mysql/my.cnf" to set global options, # - "~/.my.cnf" to set user-specific options. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # This will be passed to all mysql clients # It has been reported that passwords should be enclosed with ticks/quotes # escpecially if they contain "#" chars... # Remember to edit /etc/mysql/debian.cnf when changing the socket location. [client] port = 3306 socket = /var/run/mysqld/mysqld.sock # Here is entries for some specific programs # The following values assume you have at least 32M ram # This was formally known as [safe_mysqld]. Both versions are currently parsed. [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] # # * Basic Settings # # # * IMPORTANT # If you make changes to these settings and your system uses apparmor, you may # also need to also adjust /etc/apparmor.d/usr.sbin.mysqld. # user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql tmpdir = /tmp skip-external-locking # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer = 32M max_allowed_packet = 16M thread_stack = 192K thread_cache_size = 8 sort_buffer_size = 4M read_buffer_size = 4M myisam_sort_buffer_size = 16M # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover = BACKUP max_connections = 100 table_cache = 32 tmp_table_size = 128M #thread_concurrency = 10 # # * Query Cache Configuration # #query_cache_limit = 1M query_cache_type = 1 query_cache_size = 64M # # * Logging and Replication # # Both location gets rotated by the cronjob. # Be aware that this log type is a performance killer. # As of 5.1 you can enable the log at runtime! #general_log_file = /var/log/mysql/mysql.log #general_log = 1 log_error = /var/log/mysql/error.log # Here you can see queries with especially long duration #log_slow_queries = /var/log/mysql/mysql-slow.log #long_query_time = 2 #log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. #server-id = 1 #log_bin = /var/log/mysql/mysql-bin.log expire_logs_days = 10 max_binlog_size = 100M #binlog_do_db = include_database_name #binlog_ignore_db = include_database_name # # * InnoDB # # InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/. # Read the manual for more InnoDB related options. There are many! # # * Security Features # # Read the manual, too, if you want chroot! # chroot = /var/lib/mysql/ # # For generating SSL certificates I recommend the OpenSSL GUI "tinyca". # # ssl-ca=/etc/mysql/cacert.pem # ssl-cert=/etc/mysql/server-cert.pem # ssl-key=/etc/mysql/server-key.pem [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] #no-auto-rehash # faster start of mysql but no tab completition [isamchk] key_buffer = 16M # # * IMPORTANT: Additional settings that can override those from this file! # The files must end with '.cnf', otherwise they'll be ignored. # !includedir /etc/mysql/conf.d/ The site contains 1 wordpress site,so lots of MYISAM but mostly static content as its not changing all that often (A wordpress cache plugin deals with this). And the Magento Site which consists of a lot of InnoDB tables, some MyISAM and some INMEMORY. The "read" side seems to be running pretty well with a mass of optimizations I've used on Magento, the NGINX setup and PHP-FPM + XCACHE. I'd love to have a kick in the right direction with the MySQL config so I'm not blindly altering it based on the MySQLTuner without understanding what I'm changing. Thanks

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• ASP.NET MVC: Moving code from controller action to service layer

  - by DigiMortal

  I fixed one controller action in my application that doesn’t seemed good enough for me. It wasn’t big move I did but worth to show to beginners how nice code you can write when using correct layering in your application. As an example I use code from my posting ASP.NET MVC: How to implement invitation codes support. Problematic controller action Although my controller action works well I don’t like how it looks. It is too much for controller action in my opinion. [HttpPost] public ActionResult GetAccess(string accessCode) {     if(string.IsNullOrEmpty(accessCode.Trim()))     {         ModelState.AddModelError("accessCode", "Insert invitation code!");         return View();     }       Guid accessGuid;       try     {         accessGuid = Guid.Parse(accessCode);     }     catch     {         ModelState.AddModelError("accessCode", "Incorrect format of invitation code!");         return View();                    }       using(var ctx = new EventsEntities())     {         var user = ctx.GetNewUserByAccessCode(accessGuid);         if(user == null)         {             ModelState.AddModelError("accessCode", "Cannot find account with given invitation code!");             return View();         }           user.UserToken = User.Identity.GetUserToken();         ctx.SaveChanges();     }       Session["UserId"] = accessGuid;       return Redirect("~/admin"); } Looking at this code my first idea is that all this access code stuff must be located somewhere else. We have working functionality in wrong place and we should do something about it. Service layer I add layers to my application very carefully because I don’t like to use hand grenade to kill a fly. When I see real need for some layer and it doesn’t add too much complexity I will add new layer. Right now it is good time to add service layer to my small application. After that it is time to move code to service layer and inject service class to controller. public interface IUserService {     bool ClaimAccessCode(string accessCode, string userToken,                          out string errorMessage);       // Other methods of user service } I need this interface when writing unit tests because I need fake service that doesn’t communicate with database and other external sources. public class UserService : IUserService {     private readonly IDataContext _context;       public UserService(IDataContext context)     {         _context = context;     }       public bool ClaimAccessCode(string accessCode, string userToken, out string errorMessage)     {         if (string.IsNullOrEmpty(accessCode.Trim()))         {             errorMessage = "Insert invitation code!";             return false;         }           Guid accessGuid;         if (!Guid.TryParse(accessCode, out accessGuid))         {             errorMessage = "Incorrect format of invitation code!";             return false;         }           var user = _context.GetNewUserByAccessCode(accessGuid);         if (user == null)         {             errorMessage = "Cannot find account with given invitation code!";             return false;         }           user.UserToken = userToken;         _context.SaveChanges();           errorMessage = string.Empty;         return true;     } } Right now I used simple solution for errors and made access code claiming method to follow usual TrySomething() methods pattern. This way I can keep error messages and their retrieval away from controller and in controller I just mediate error message from service to view. Controller Now all the code is moved to service layer and we need also some modifications to controller code so it makes use of users service. I don’t show here DI/IoC details about how to give service instance to controller. GetAccess() action of controller looks like this right now. [HttpPost] public ActionResult GetAccess(string accessCode) {     var userToken = User.Identity.GetUserToken();     string errorMessage;       if (!_userService.ClaimAccessCode(accessCode, userToken,                                       out errorMessage))     {                       ModelState.AddModelError("accessCode", errorMessage);         return View();     }       Session["UserId"] = Guid.Parse(accessCode);     return Redirect("~/admin"); } It’s short and nice now and it deals with web site part of access code claiming. In the case of error user is shown access code claiming view with error message that ClaimAccessCode() method returns as output parameter. If everything goes fine then access code is reserved for current user and user is authenticated. Conclusion When controller action grows big you have to move code to layers it actually belongs. In this posting I showed you how I moved access code claiming functionality from controller action to user service class that belongs to service layer of my application. As the result I have controller action that coordinates the user interaction when going through access code claiming process. Controller communicates with service layer and gets information about how access code claiming succeeded.

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• Different Flavors of Leases Back On

  - by Theresa Hickman

  Given the continued interest regarding the proposed changes to Lease Accounting, I decided to write another entry on this controversial topic with colorful commentary from our resident accounting expert, Seamus Moran. Background (A History Lesson) Back in 1976, the FASB issued FAS 13, “Accounting for Leases” that permitted leases to be either an operating lease or capital (finance) lease. In substance, operating leases are a form of off-balance sheet financing. According to Seamus, operating leases date back to the launch of the Boeing 707 in the 1950s.  Because the aircraft was so much more expensive than previous aircrafts, the industry came up with the operating lease concept to accommodate these jet liners that dominated air transport.  How it worked was the bank would buy the plane and lease it to the airline.  Because the bank never controlled or flew the plane, they never placed the asset on their balance sheet, and because the airline never owned the plane, they didn’t place it on their balance sheet either. They simply treated the monthly lease payments as rental expenses on the P&L.   August 2010 Original Lease Accounting Changes In August 2010, FASB and IASB decided to overhaul lease accounting as part of their joint commitment “to insure that investors and other users of financial statements are provided useful, transparent, and complete information about leasing transactions in the financial statements.”  Some say that the current lease accounting standards are broken because it keeps assets off the balance sheet, hidden from investors’ view. The original proposal abolished operating leases and only permitted capital leases where all leases would be recorded on the balance sheet as assets and liabilities. The asset side would reflect the right to use the asset for the leased term, and the liability side would reflect the obligation to make lease payments.   Why Companies Were Freaking Out According to the SEC, the financial impact of the aforementioned lease changes was estimated to add more than $1.3 trillion of operating lease obligations to corporate balance sheets. Many companies in various industries, especially retail, are concerned because the changes are significant and will impact existing leases with no grandfather clause for existing operating leases. Of course, the banks and airlines I mentioned earlier really hate this because neither wants to report the airplane (now costing around $60 M) as an asset. Regular companies were concerned that they would have to report routine short term leases of real estate or equipment as fixed assets, even though they were really just longer term rentals.  One company we spoke to leased roadside billboards, and really did not consider them to be fixed assets in any way. Obviously, these changes would have had a profound and lasting effect on a company’s financial and real estate strategies and significantly impact its financial statements.  Financial statements would show higher depreciation and interest expense with significantly higher total assets and debt. In terms of financial metrics, they’re negatively impacted. It would raise a company’s debt-to-capital ratio to reflect the higher debt compared to equity, it would negatively impact their return-on-assets because now companies will appear more asset intensive, and it will decrease EPS, lowering shareholder ROI. Feb. 2011 Recent Update The comment period on leases closed in December 2010. The FASB and the IASB have met several times since then and published their initial responses to the input they received from the various interested parties.  They are “redeliberating” the principles involved in Lease Accounting.  Some of the issues they are looking at include: The core definition of a lease.  This will articulate principles on what is a lease and what is “not-a-lease.” One theory or supposition is that they might define a lease as the transfer of certain but not all major ownership attributes for a certain period of time.  So a year’s lease of an aircraft might be a “lease,” but a year’s lease of half a floor in an office building would be “not-a-lease.”  The ownership attributes transferred from the core owner to the user are different; the airline must maintain, paint, and do whatever it needs to do on the aircraft. However, the office renter will have strictly limited rights in respect to the rented space. The differences between a lease contract and service contract.  Even if they call them “leases” for the purpose of commercial law, a service contract might not be accounted for as a lease. The accounting to be done by the lessee.  They would define when the bank or landlord would retain the asset on their balance sheet, and perhaps by implication, when the lessor would not need to include the asset on theirs.  So if the finance house keeps the airplane or office on their balance sheet, the tenant doesn’t need to.  I’m not sure that I can draw the opposite conclusion where the finance house doesn’t report but the tenant must. The difference, if any, between a financing lease and other leases, and the implications to the accounting. The present value calculation when renewable terms exist. They have reduced the circumstances in which one must look at the renewable terms of a lease in calculating the present value.  In most circumstances, you will use the lease term rather than the potential renewable term. Their latest discussion this past week with the contents of the discussion was not available at the time of me writing this entry.  For more details, the results of the discussions are posted on both the FASB and the IASB websites. Implied Software Changes Whatever the final rules turn out to be, all ERP systems, such as Oracle E-Business Suite, PeopleSoft Enterprise, JD Edwards, and Oracle Hyperion will need to change their software to accommodate the new rules. The following lists some changes that might have to be made to accounting software depending on what the final standards will be in June 2011: Lease tracking may require modifications with tracking of additional lease details that might require a centralized repository to maintain Accounting may need to be modified as there are many changes to how capital leases and the new “other than finance” leases are accounted for both on the lessee and lessor side.  For example, valuation, amortization, and disclosure will be considerably different requiring different types of data to be captured. Companies may need to modify their chart of accounts depending on how they want to track leases, which could then impact financial reporting and consolidation Business processes may require changes which could then impact internal controls Software applications may need to perform more advanced computations on leases Reports and KPIs may need to reflect new operating metrics Hold Onto Your Seats           Before you redo all your lease agreements and call your software vendors asking when the changes to the software will be made, remember that the rules are not finalized yet, and from appearances, will not reflect the proposals in the exposure draft.  Not only are there objections to putting the operating lease assets on anyone’s balance sheet, there are lots of objections to subjectivity and the data required for the valuation.  According to Seamus, there is huge opposition from New York bankers, the airlines, the EU, the Communist Party of China (since it impacts their exporting business), and Republicans (hearing complaints from small and large businesses). Even if everyone can agree on the proposed changes, 2013 might be the earliest that companies would need to change how they report leases. The Boards will finish their deliberations in April, May or June 2011.  As we’ve seen with other Exposure Drafts, if the changes are minor and the principles met the General Acceptance consensus criteria, the Standard could be finalized at that time.  However, if substantial changes are made, a fresh exposure draft, comment period, and review period might be involved, too. Seamus added an interesting perspective. Even if the proposed changes do pass, don’t you think our customers, such as Boeing, GE Capital, United Airlines, etc. will be clever enough to come up with a new kind of financing arrangement that complies with the new accounting? How about the large retail customers, such as Best Buy and Macerich? Don’t you think they might simply cut deals around retail locations with new contracts that prevent their leases from being capital leases? Instead of blindly adapting the software to meet the principles outlined in the final standard, our software needs to accommodate how businesses will respond to the new rules. We cannot know our customers’ responses until the rules are finalized. Oracle is aware of the potential changes and is staying abreast of the developments through our domain expertise staff, our relationship with customers, our market awareness, and, of course, our relationships with the Big 4. This is part of our normal process with respect to worldwide regulatory compliance. Oracle products have been IFRS and GAAP compliant for years and we will continue to maintain those standards going forward.

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• SQL SERVER – Weekly Series – Memory Lane – #007

  - by pinaldave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Find Stored Procedure Related to Table in Database – Search in All Stored Procedure In 2006 I wrote a small script which will help user  find all the Stored Procedures (SP) which are related to one or more specific tables. This was quite a popular script however, in SQL Server 2012 the same can be achieved using new DMV sys.sql-expression_dependencies. I recently blogged about it over Find Referenced or Referencing Object in SQL Server using sys.sql_expression_dependencies. 2007 SQL SERVER – Versions, CodeNames, Year of Release 1993 – SQL Server 4.21 for Windows NT 1995 – SQL Server 6.0, codenamed SQL95 1996 – SQL Server 6.5, codenamed Hydra 1999 – SQL Server 7.0, codenamed Sphinx 1999 – SQL Server 7.0 OLAP, codenamed Plato 2000 – SQL Server 2000 32-bit, codenamed Shiloh (version 8.0) 2003 – SQL Server 2000 64-bit, codenamed Liberty 2005 – SQL Server 2005, codenamed Yukon (version 9.0) 2008 – SQL Server 2008, codenamed Katmai (version 10.0) 2011 – SQL Server 2008, codenamed Denali (version 11.0) Search String in Stored Procedure Searching sting in the stored procedure is one of the most frequent task developer do. They might be searching for a table, view or any other details. I have written a script to do the same in SQL Server 2000 and SQL Server 2005. This is worth bookmarking blog post. There is an alternative way to do the same as well here is the example. 2008 SQL SERVER – Refresh Database Using T-SQL NO! Some of the questions have a single answer NO! You may want to read the question in the original blog post. I had a great time saying No! SQL SERVER – Delete Backup History – Cleanup Backup History SQL Server stores history of all the taken backup forever. History of all the backup is stored in the msdb database. Many times older history is no more required. Following Stored Procedure can be executed with a parameter which takes days of history to keep. In the following example 30 is passed to keep a history of month. 2009 Stored Procedure are Compiled on First Run – SP taking Longer to Run First Time Is stored procedure pre-compiled? Why the Stored Procedure takes a long time to run for the first time?  This is a very common questions often discussed by developers and DBAs. There is an absolutely definite answer but the question has been discussed forever. There is a misconception that stored procedures are pre-compiled. They are not pre-compiled, but compiled only during the first run. For every subsequent runs, it is for sure pre-compiled. Read the entire article for example and demonstration. Removing Key Lookup – Seek Predicate – Predicate – An Interesting Observation Related to Datatypes This is one of the most important performance tuning lesson on my blog. I suggest this weekend you spend time reading them and let me know what you think about the concepts which I have demonstrated in the four part series. Part 1 | Part 2 | Part 3 | Part 4 Seek Predicate is the operation that describes the b-tree portion of the Seek. Predicate is the operation that describes the additional filter using non-key columns. Based on the description, it is very clear that Seek Predicate is better than Predicate as it searches indexes whereas in Predicate, the search is on non-key columns – which implies that the search is on the data in page files itself. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL Server – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administration assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. 2010 Recycle Error Log – Create New Log file without Server Restart Once I observed a DBA to restaring the SQL Server when he needed new error log file. This was funny and sad both at the same time. There is no need to restart the server to create a new log file or recycle the log file. You can run sp_cycle_errorlog and achieve the same result. Get Database Backup History for a Single Database Simple but effective script! Reducing CXPACKET Wait Stats for High Transactional Database The subject is very complex and I have done my best to simplify the concept. In simpler words, when a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. Threads which came first have to wait for the slower thread to finish. The Wait by a specific completed thread is called CXPACKET Wait Stat. Information Related to DATETIME and DATETIME2 There are quite a lot of confusion with DATETIME and DATETIME2. DATETIME2 is also one of the underutilized datatype of SQL Server.  In this blog post I have written a follow up of the my earlier datetime series where I clarify a few of the concepts related to datetime. Difference Between GETDATE and SYSDATETIME Difference Between DATETIME and DATETIME2 – WITH GETDATE Difference Between DATETIME and DATETIME2 2011 Introduction to CUME_DIST – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function CUME_DIST(). This function provides cumulative distribution value. It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. Introduction to FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical functions FIRST_VALUE() and LAST_VALUE(). This function returns first and last value from the list. It will be very difficult to explain this in words so I’d like to attempt to explain its function through a brief example. Instead of creating a new table, I will be using the AdventureWorks sample database as most developers use that for experiment purposes. OVER clause with FIRST _VALUE and LAST_VALUE – Analytic Functions Introduced in SQL Server 2012 – ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING “Don’t you think there is bug in your first example where FIRST_VALUE is remain same but the LAST_VALUE is changing every line. I think the LAST_VALUE should be the highest value in the windows or set of result.” Puzzle – Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY You can see that row number 2, 3, 4, and 5 has same SalesOrderID = 43667. The FIRST_VALUE is 78 and LAST_VALUE is 77. Now if these function was working on maximum and minimum value they should have given answer as 77 and 80 respectively instead of 78 and 77. Also the value of FIRST_VALUE is greater than LAST_VALUE 77. Why? Explain in detail. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This functions accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. Instead of creating new table, I will be using AdventureWorks sample database as most of the developer uses that for experiment. A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available Our book was out of stock in 48 hours of it was arrived in stock! We got call from the online store with a request for more copies within 12 hours. But we had printed only as many as we had sent them. There were no extra copies. We finally talked to the printer to get more copies. However, due to festivals and holidays the copies could not be shipped to the online retailer for two days. We knew for sure that they were going to be out of the book for 48 hours. This is the story of how we overcame that situation! Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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