You probably have either very large or very many sessions which Tomcat is attempting to reload on startup. Tomcat serialises sessions into files called SESSIONS.ser (in the application directories under the work dir) and then when it is restarted it attempts to reload them all. I presume this behaviour can be turned off.
In terms of testing your app, you want to figure out whether you have a memory leak issue with your app, or simply that your max heap size is set too low for the load you are running. To check for memory leaks, you could run jmeter reasonably (although not too hard) excercising as much of your app as you can, repetitively and for an extended period. If it eventually keels over then you may need to investigate memory leaks with a profiler. Another possibility is that you may not be invalidating sessions and they are just being left to expire naturally. This can use up a lot of memory if you aren't careful and I supect is a quite likely source of your problems. Cheers! -----Original Message----- From: Guillaume Lahitette [mailto:[EMAIL PROTECTED] Sent: 03 March 2005 09:51 To: tomcat-user@jakarta.apache.org Subject: OutOfMemory / JMeter / Profiler questions Hello Tomcat'oids! We've started performance testing one of our REMOTE web apps using JMeter. We're gathering benchmark data before doing further fine tuning. Details: Win2K only have ssh + cygwin access to this remote server JDK 1.4.1_03 Tomcat 4.1.26, running as a service: a.. Use security manager 1 b.. Security policy file D:\Tomcat4\conf\catalina.policy c.. Initial heap 256 d.. Max heap 512 e.. Stack size 256 f.. JVM server Issue: We are getting OutOfMemory errors with very few threads simulated (as low as 5). More problematic, we've seen the OOM just after a Tomcat service restart! >From the stack trace below, you can see we get the OOM before any of our code >is executed :( Questions: a.. Anyone has seen this behavior upon Tomcat start up? b.. Anything particular to watch for in our JMeter test plan? c.. Would a profiler help? Could it profile a remote Tomcat installation? Any +/- feedback on Eclipse Profiler plug in (http://eclipsecolorer.sourceforge.net/index_profiler.html)? We'll work on gathering more data (e.g. periodic free / allocated memory dumps). Untill then, thank you for sharing your experiences, suggestions, code,...! Cheers, Guillaume javax.servlet.ServletException: Servlet execution threw an exception at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269) at org.apache.catalina.core.ApplicationFilterChain.access$000(ApplicationFilterChain.java:98) at org.apache.catalina.core.ApplicationFilterChain$1.run(ApplicationFilterChain.java:176) at java.security.AccessController.doPrivileged(Native Method) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:172) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2416) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:577) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174) at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480) at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995) at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:601) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392) at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565) at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619) at java.lang.Thread.run(Thread.java:536) root cause java.lang.OutOfMemoryError --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
