incorrect implementation of IAsyncResult: What is this error? How do I fix it?

Question

I am using the standard run of the mill WCF framework in .NET 4.0 to evaluate the framework so that we can be ready to begin developing in it when it gets released. I have a client that is sending string data to a WCF service hosted under IIS on a test server and is expecting a response. Periodically I get the following error in my server logs:

Event Type: Error
Event Source: ASP.NET 4.0.30128.0
Event Category: None
Event ID: 1325
Date:  3/17/2010
Time:  1:18:03 PM
User:  N/A
Computer: [REMOVED]
Description:
An unhandled exception occurred and the process was terminated.

Application ID: /LM/W3SVC/1234452652/Root

Process ID: 1256

Exception: System.InvalidOperationException

Message: An incorrect implementation of the IAsyncResult interface may be returning incorrect values from the CompletedSynchronously property or calling the AsyncCallback more than once. The type System.Data.Common.DbAsyncResult could be the incorrect implementation.

StackTrace:    at System.Runtime.AsyncResult.ThrowInvalidAsyncResult(IAsyncResult result)
   at System.Runtime.AsyncResult.AsyncCompletionWrapperCallback(IAsyncResult result)
   at System.Runtime.Fx.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
   at System.Data.Common.DbAsyncResult.AsyncCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Data.Common.DbAsyncResult.ExecuteCallback(Object asyncResult)
   at System.Threading.QueueUserWorkItemCallback.WaitCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean ignoreSyncCtx)
   at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
   at System.Threading.ThreadPoolWorkQueue.Dispatch()
   at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback()

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Now, an initial search for info yeilded only one result: http://blogs.msdn.com/toddca/Default.aspx?p=2

While this provides some great information under: IIS 6 Crashing With Some Asynchronous Handlers

It does not provide a fix or solution. Is this a bug in the framework/IIS that might be corrected in the release? Should I host it in an alternative fashion? Can anyone provide some additional information on this problem.

Thanx.

Answer 1

I am sorry, but I do not find any useful information in the links you provided. Can you publish some more information about your service so we may be able to help here? Is it a WF or a WCF service?

Answer 2

Here is the precise link to the information that I found about this problem:

http://blogs.msdn.com/toddca/archive/2006/01/03/iis-6-crashing-with-some-asynchronous-handlers.aspx

I am not sure wat additional information you would like.

It is a WCF service.

Here is the contract definition:

[ServiceContract(Name = "ObjectService", Namespace = "urn:IPMC.Object/2010/03")]

public interface IObjectService{ 

[OperationContract(Name = "AddObject")] 
TransactionResult AddOject(TestObject obj, bool useConfirm);

}

I would be happy to provide the contracts for TestObject and TransactionResult if they are needed.

Answer 3

Have you read the MSDN documentation that explains how to call WCF service operations asynchronously?

http://msdn.microsoft.com/en-us/library/ms731177.aspx

http://msdn.microsoft.com/en-us/library/ms730059.aspx

Hope this helps.

Answer 4

Amadeo,

That is the problem... I am calling the WCF service synchronously.

T.J.

Answer 5

Can you send me a small repro to amadeoc AT microsoft.com so I can see where the problem is?

I still do not see what the features of your service are... Have you tried running any of the WCF 4.0 samples? Do they run for you? In which sense is your service different from the WCF samples that you can download from: http://www.microsoft.com/downloads/details.aspx?FamilyID=35ec8682-d5fd-4bc3-a51a-d8ad115a8792&displaylang=en?