Max concurrent sessions for WCF using IIS and Asynch methods

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Hi there,

I am calling a WCF service from a form. Service is hosted in IIS. The service with the following attributes: InstanceContextMode.PerSession, ConcurrencyMode = ConcurrencyMode.Multiple

I have set the throttling behaviour to max out at 2000 for all concurrent calls, instances and sessions.

However I cant seem to get more than 200 sessions concurrently. After that the service just does not respond, and the session eventually times out.

I am using an Asynch call to call the method in the service ie

C#

IASyncResult res= Proxy.BeginMethod(endCall,null);

and then to catch the response I have a endCall function that takes in the IASyncResult and processes the result via EndMethod().

in a load simulation @ 1 method call a second, it all works fine until around 200 calls, and then just waits... (I have 199 or 198 responses from those 200 calls at this point in time)..

Perhaps there is some garbage collection or closing that I am not doing?
any suggestions?

Posted 17-Sep-11 2:13am

faroukg

Updated 17-Sep-11 3:39am

Herman<T>.Instance

v2

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Herman<T>.Instance · Answer 1 · 2011-09-17T03:38:00

Solution 1

Where you place null in your code (the state) you better set Proxy as value.
In the EndMethod you first do:

C#

Proxy myProxy = (Proxy)ar.AsyncState; // assuming ar is declared as IASyncRestult name in method

in that case you do threadsafe asynchronous calls.

Posted 17-Sep-11 3:38am

Herman<T>.Instance

Comments

faroukg 17-Sep-11 10:57am

so in the EndMethod:

Collapse | Copy Code

{
MyServiceRef.MyServiceClient myProxy = (MyServiceRef.MyServiceClient) callRes.AsyncState;

int res = myProxy.EndMethod(callRes); //callRes is my IASyncResult

}

??

Herman<T>.Instance 17-Sep-11 14:14pm

correct, that is the threadsafe way!

faroukg 17-Sep-11 14:23pm

ok tried that..still doesnt solve the problem... still only get to 200 and then the asynch calls just "wait" till timeout

Herman<T>.Instance 18-Sep-11 9:34am

is your service set up as httpmodule?

faroukg 18-Sep-11 13:42pm

i am not sure.. where do i see this, and what do i set it to?

Herman<T>.Instance 18-Sep-11 14:32pm

httpmodule are setup in the web.config

faroukg 18-Sep-11 15:52pm

what do i set it to?

Herman<T>.Instance 19-Sep-11 3:13am

the point is. I do not know your project structure. SO I do not know when the call is made. I guess all data is collected in the renderthread in stead of in the workerthreads. When using too many renderthreads at the same time you webserver crashes. By creating a service as httpmodule you can have he async work setup in a workerthread. That is where I want to bring you

faroukg 19-Sep-11 5:32am

I created a net.tcp endpoint and used that but still get the same problem.

will a nettcp binding not overcome the need for httpmodule?

to answer your previous question:
the call is made during an On_Click event. the even spawns a threat (until clicked again - then the thread is aborted).

in this thread a infinite loop calls the Asynch method once a second ie beginMethod. The result is fetched in the endMethod.

Herman<T>.Instance 19-Sep-11 5:41am

is the page setup async with a registerasynctask? In that case the processing is done in a workerthread and not in a renderthread

faroukg 19-Sep-11 16:12pm

nope the windows form just runs the default created Proxy.BeginMethod (when selecting "generate asynch methods" in the service reference.
the method takes in a callback function. In the call back function I find the return result.

Herman<T>.Instance 20-Sep-11 4:51am

in your tags you mention IIS. I thought you were creating a website.....
The method for HTTPModule is of now use for you.... that's a pitty. Give me some thinking time