Our Tomcat 6.0.29 goes down after reaching its maximum number of Threads. I would really appreciate any help with it because it is a production server.

Here is part of the catalina.log file:

INFO: Maximum number of threads (600) created for connector with address null and port 80 Mar 8, 2011 11:19:37 AM org.apache.coyote.http11.Http11Protocol pause

INFO: Pausing Coyote HTTP/1.1 on http-80 Mar 8, 2011 11:19:38 AM org.apache.catalina.core.StandardService stop

INFO: Stopping service Catalina Mar 8, 2011 11:19:38 AM org.apache.catalina.core.StandardWrapper unload

INFO: Waiting for 8 instance(s) to be deallocated


There is no code in Tomcat that triggers a shutdown when the thread pool is fully utlised. You need to look for an external process that is doing this. Maybe some form of watchdog process that tries to connect to Tomcat, can't because all the threads are in use so it stops / restarts Tomcat?


Perhaps there are 600 instances of servlets that are doing work, so none are available and Tomcat can't do anything about that?

I get the impression that that might be the case from the bottom of this post that talks about JBoss (which uses Tomcat under the covers): forum post

  • I'm wondering why it takes the server down!!! because as far as I know when the number of thread exceeds it's max Tomcat would cache new requests till some threads become available. And it is just Tomcat, no other app server. Thanks Jon.
    – user73628
    Mar 8 '11 at 23:15
  • Yeah it really doesn't make sense why the server should come down when that happens. Can you determine what code is being the bottleneck (if that's the case)? You can try attaching a profiler to the JVM that tomcat is running in, that might help narrow down the problem. Mar 8 '11 at 23:24

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