I'm sure this has been asked before, but since I cannot search the forum I'll ask it again.
I have a connection to the host, in my case TN3270e. The project is a Web services project, but I doubt that matters to the crux of the question, using chained IOs.
Our client runs FIC and logs in, one or more MIC, then remains idle for a prolonged period of time, say 2-3 hours. Is there any "keep-alive" talking going on the Telnet connection during the idle period? I believe not, but I need to make sure. The host basically has disabled the idle timeout, so it is possible that an idle connection will sit there for days, e.g across a weekend, unless some external action occurs, such as cycling the CICS application. If the Web services client servlet were to be reset, then no LIC would be sent to release the connection. Then if the Web services client were to restart all new connections would be established.
I curious if there might be some activity that the host could do or look for, at an IP level, that would indicate that the client was gone and automatically clean up.
The above scenario is happening and when it does a couple of things occur:
- The host pool of LUs becomes exhausted causing the connections to fail.
- If the pool is sufficiently large the WAS server runs out of available ports/threads and hangs. Then trying to terminate that application will result in the Telnet sessions being released, but the threads are still hung and attempt to terminate may fail.
Has anyone seen this last scenario before? This condition only happens under extreme load. I would expect this condition to have been encountered during performance testing that resulted in the recommendations document.
Any feedback would be appreciated.