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POWill Entity Framework fail when running on a high volumn IIS web site
 

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  1. POWill Entity Framework fail when running on a high volumn IIS web site
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    <p>We have been trying to analyse this exception:</p> <blockquote> <p>Message: Error: Object reference not set to an instance of an object.. Stacktrace: at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean&amp; canBeCached, RuntimeMethodHandleInternal&amp; ctor, Boolean&amp; bNeedSecurityCheck) at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache) at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean skipCheckThis, Boolean fillCache) at System.Activator.CreateInstanceT at Z.Services.ObjectContextManagement.ScopedObjectContextManager<code>1.get_ObjectContext() at Z.Services.DatabaseAccess.DatabaseAccess</code>2.Manage() at Z.Services.DatabaseAccess.DatabaseAccess`2.get_ObjectContext()</p> </blockquote> <p>Basically we get an error when getting the ObjectContext.</p> <p>From this question: <a href="https://stackoverflow.com/questions/2575990/entity-framework-lazy-loading-doesnt-work-from-other-thread">Entity Framework lazy loading doesn&#39;t work from other thread</a> we see that EF is dependent upon staying on the same thread.</p> <p>From this Jon Skeet's answer to this question: <a href="https://stackoverflow.com/questions/1643987/will-a-request-in-iis-run-on-a-single-thread">Will a request in IIS run on a single thread?</a> we see that IIS has thread agility.</p> <p>When there is a lower traffic volumn we do not see this error, but when the load increases we see the error.</p> <p>So the question: If EF is dependent upon staying on a single thread, and IIS does not keep the request on a single thread, can EF be used on an application that is deployed on IIS?</p> <p><strong>Edit</strong></p> <pre><code>var frameworkAssembly = Assembly.GetAssembly(typeof(ObjectContextManager&lt;&gt;)); var managerType = frameworkAssembly.GetType(managerTypeName + "`1", true, true); managerType = managerType.MakeGenericType(typeof(TObjectContext)); ObjectContextManager = Activator.CreateInstance(managerType) as ObjectContextManager&lt;TObjectContext&gt;; </code></pre> <p>It appears that the error occurs on the last line of the above code. The error only occurs in production under heavy load.</p> <p><strong>Edit 2</strong></p> <p>The ObjectContextManager inherits from ObjectContext which is an EF class.</p> <pre><code> public abstract class ObjectContextManager&lt;T&gt; where T : ObjectContext </code></pre>
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    1. USShiraz Bhaiji
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    1. COGiven that EF IS deployed on a lot of web sites without problems, you should probaly check what you are doing wrong. Can you show the offending code?
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      1. USPanagiotis Kanavos
    2. CO@PanagiotisKanavos Thanks for the comment, I have updated the question
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    3. COThis isn't EF code. This is about Activator failing to create a type. Are you sure managerType isn't null? BTW what is ObjectContextManager? Why are you creating the class like this? Why not just pass the context type as a type parameter?
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