> From: Tomcat Novice [mailto:tomcat.novice@gmail.com]
> Subject: Tomcat Thread utilization growing very large causing a hung
> tomcat instance
>
> I have been encountering issues where a particular tomcat
> instance/s are having large thread count during load testing
> and results in a hung state.
I suspect that your code is spawning threads, and not managing them properly. Your horribly
formatted stack trace shows timer threads being started by:
at com.hp.ov.sm.client.common.communications.HeartBeat.(HeartBeat.java:68)
at com.hp.ov.sm.client.common.communications.SOAPClient.connect(SOAPClient.java:237)
at com.hp.ov.sm.client.webtier.WebClient.connect(WebClient.java:95)
at com.hp.ov.sm.client.webtier.WebController.init(WebController.java:599)
at com.hp.ov.sm.client.webtier.WebControllerServlet.index(WebControllerServlet.java:448)
at com.hp.ov.sm.client.webtier.WebControllerServlet.process(WebControllerServlet.java:366)
at com.hp.ov.sm.client.webtier.WebControllerServlet.processHTTPRequest(WebControllerServlet.java:317)
at com.hp.ov.sm.client.webtier.WebControllerServlet.doGet(WebControllerServlet.java:255)
(The next time, leave the line breaks in the trace, please.)
> 1. Any ideas how I can resolve/isolate this problem?
Fix your webapp to manage threads properly.
> 2. I know I need to do a thread dump but I am not familiar on how to
> analyze thread dumps from Tomcat. Can you point me to documententation
> on how I can analyze thread dumps from Tomcat?
Take a thread dump on a Tomcat that's been used but now idle, and then one on the problematic
system, and compare.
> 3. Also, can someone confirm if the thread dumps from JDK 1.5 are the
> same as the Thread Dumps from a JDK 1.6? I seem to be getting different
> formats. Can someone just confirm?
I don't recall any major differences, but they are unlikely to be identical, since minor enhancements
to the JVM are made all the time.
> 4. If the maxThread is set to 200, why are the Tomcat instances
> utilizing up to 400 Threads (see screenshot)
There isn't a screenshot (the mailing list strips most attachments). Post data, not pictures.
Also post your server.xml so we can see what you have configured, but please remove the commented-out
bits (and passwords) before doing so.
- Chuck
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