Connections to Dispatcher Hang and May Be in CLOSE_WAIT
(Doc ID 1581632.1)
Last updated on OCTOBER 28, 2024
Applies to:
Oracle Communications Messaging Server - Version 5.2.0 and laterAll Platforms
Symptoms
On Solaris 11 update 1, during SMTP load testing, the dispatcher builds up TCP socket connection file descriptors in CLOSE_WAIT state until it reaches MAX_HANDOFFS, at which point it will not accept any more connections. Restarting dispatcher briefly clears the situation.
The client connects and never receives the banner. A normal client would time out and retry. End users may get a "connection failed" type error. Remote MTAs may see this as poor performance.
A load test program that does not timeout will see this as a hung connection or hung test thread.
Watching the dispatcher with truss, or enabling debugs, slows it down enough to prevent the problem from happening.
Watching the dispatcher with truss -t sendmsg may see sendmsg() fail with errno=11, EAGAIN -- if the system is fast enough and that truss does not slow it down too much.
Watching the dispatcher with dtrace -n 'syscall::sendmsg:return/arg0/{printf("pid=%d errno=%d\n",pid,errno);}' -p <dispatcher-pid>; shows sendmsg() failing with errno=11, EAGAIN.
Changes
Running on Solaris 11 update 1.
Solaris 11 became a "supported platform" as of Communications Suite 7.0.5 (which contains Messaging Server 7.0.5.29):
- Requirements for Communications Suite 7.0.5.0.0 - https://docs.oracle.com/cd/E49303_01/doc/ucs_705_install_guide.pdf#page=2213&zoom=auto,0,647.55
Solaris 11 will certainly never be a supported platform for Messaging Server 5.2. However, it was possible to run Messaging Server 5.2 on Solaris 10. And this problem could happen in that scenario. Note: Messaging Server 5.2 is long past End of Support Life. This problem was originally observed with Messaging Server 7.0.5.28 running in a Solaris 10 Branded Zone on Solaris 11.
Cause
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In this Document
Symptoms |
Changes |
Cause |
Solution |
References |