Symptoms
When you run a 64-bit application that's trying to establish hundreds of sessions at startup very quickly, some sessions aren't established and remain in a "Status pending" state.
Cause
This issue occurs because of a limitation that allows for only 512 outstanding requests. This limitation is called MAX_PENDING_RPCREQ. It was increased to 5,120.
Resolution
Microsoft Host Integration Server 2010
Currently, no fix is available for Host Integration Server 2010. A fix for this issue in Host Integration Server 2010 is scheduled to be provided in the next cumulative update (cumulative update 11) for Host Integration Server 2010.
Microsoft Host Integration Server 2013
The fix for this problem is included in cumulative update package 3 for Host Integration Server 2013. For more information about how to get the cumulative update package, see Cumulative update package 3 for Host Integration Server 2013.
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
