What can cause MapRequestHandler to hang?

Question

I am running a SOAP web service on IIS 8.5 on a Windows Server 2012 R2 x64 bit.

Ever so often a request hangs. These requests will usually take about 60 ms but then sometimes it takes 45 secs or more.

I have New Relic installed on the server, and the stack trace tells me that all the extra time is spent in MapRequestHandler. New Relic doesn't offer any more information than this.

I have tried searching for information on what happens in MapRequestHandler but haven't been able to find any indication on why this would happen. I am able to reproduce this every 10th request or so. But I still have no indication of what is actually happening. I am not able to reproduce it in my development environment, only in production.

Is there anything I should be logging to get more information?

Any idea what might cause this? I don't see any unusual load on my system.

Tyre

did you get any further with this? - we're experiencing similar problems. – Sanjiv

I am afraid we didn't find any conclusive answer. The only thing we could think of that could cause this was a problem with our session state sql servers. We have seen some blocking chains. We are already in the process of moving to a stateless architecture, so since this is not something we see often, we decided to leave it. – Tyre

ok, thanks for the response. We have a stateless architecture already, so these problems may be unrelated anyway. – Sanjiv

Have a colleague with a similar problem. Have offered a bounty for an answer. – Capetian

Be sure to use New Relic's Thread Profiler, if you haven't already. This will give a performance view across the application at the time of the hang, as opposed to just the stack trace details and durations on a single Transaction Trace. Where the time is spent during the profiler session might give additional insight. – Cambyses

Maybe this link can help leansentry.com/Guide/IIS-AspNet-Hangs – Parsnip