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From LeeAnn Pultz <lee...@extraview.com>
Subject Re: OutOfMemoryError - 100 thread limit?
Date Wed, 20 Apr 2005 15:57:29 GMT
We have no jsps in the application.  The index.html page loads our servlet 
class, and I've put logging of active number of threads at the beginning of 
the servlet ini() and the very end of the service() methods in that servlet 
class.  The application initializes, but we aren't doing any of the real 
"work" of rendering dynamic pages or talking to the database at this point.

I get the same results whether my Xmx is 84 megs or 512 megs - we're just 
not using that much memory.




At 08:48 AM 4/20/2005, Peter Lin wrote:
>that sounds very odd. so if I understand correctly. this happens when
>you hit the login page. I assume this don't happen with a static html
>page?  by any chance are you using jsp tags or some web framework?
>
>peter
>
>
>On 4/20/05, LeeAnn Pultz <leeann@extraview.com> wrote:
> > This is not a memory leak in the application - we have hooked up a profiler
> > to the application and watched the actual memory usage when causing this
> > issue to happen.  We have lots of memory available, are nowhere near the
> > Xmx limit, and the machine has lots of memory available over and above the
> > Xmx limit.
> >
> > In fact, I can cause the error to happen every single time, simply by
> > hitting the first web page (login page) of the application - I don't have
> > to log in, or do any "work".  All I have to do to get the error to happen
> > is hit 18-19 different instances of the web application, watch the Active
> > thread count go up to 100 and tip over the tomcat.
> >
> > We've gone through all of the suggested infomation out on the web - we've
> > tweaked the Xms, Xmx and Xss parameters  - none of these changes made any
> > difference, since we're not actually running out of memory.  I've
> > reproduced this on 3 different machines, all running Red Hat Linux ES 3.0 -
> > both with LD_ASSUME_KERNEL 2.4.19 and without, so the Linux threading model
> > doesn't seem to affect the problem.
> >
> >
> > At 04:16 AM 4/20/2005, you wrote:
> > >I'm able to go up to 647 threads and 500 concurrent connections with
> > >5.5.4 without any problems. chances are, it's a memory leak in the
> > >webapp. only way to know for sure is to profile the application.
> > >
> > >peter lin
> > >
> > >
> > >On 4/20/05, Tim Funk <funkman@joedog.org> wrote:
> > > > There are no limits in tomcat.
> > > > http://jakarta.apache.org/tomcat/faq/memory.html
> > > >
> > > > -Tim
> > > >
> > > > LeeAnn Pultz wrote:
> > > >
> > > > > I have a tomcat server with multiple copies of our web application
> > > > > running.  We are running into what seems to be a hard-coded limit

> on the
> > > > > number of threads available to the Tomcat application.
> > > > >
> > > > > I have added code to our servlet class which prints out the number
of
> > > > > active threads whenever I initialize the servlet.  On Red Hat Linux
> > > > > boxes, whenever we start up enough copies of the servlet to hit 100
> > > > > active threads, we reach an OutOfMemoryError - regardless of the

> Xms/Xmx
> > > > > settings (memory profiling shows that we have plenty of memory
> > > > > available).  On Windows XP, 50 seems to be the magic number.
> > > > >
> > > > > I have tried tweaking Xss parameters, my ulimit command in Linux

> shows
> > > > > "unlimited" - and I have reached the same results with Tomcat 3.3.1,
> > > > > 4.0.28 and 5.0.28 using Java 1.4.1 and 1.4.2.  When I use 
> WebLogic 8.1
> > > > > on the same Linux box, I reach 241 active threads with no problems
> > > > > whatsoever (stopped my testing at that number) so it does not 
> seem to be
> > > > > an o/s limitation, or a java limitation - which leads me to believe
> > > > > there is something in Tomcat?
> > > > >
> > > > > Is the number of threads available to tomcat hard coded somewhere?
Is
> > > > > there a parameter or configuration setting that I can change to 
> increase
> > > > > this?
> > > > >
> > > > > If this question is better off posted to the developers list, please
> > > > > someone, let me know :)
> > > > >
> > > >
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> > > >
> > >
> > >---------------------------------------------------------------------
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> >
> > LeeAnn Pultz
> > ExtraView Corporation
> > leeann@extraview.com
> > 831-461-7100 x115
> >
> >
> > ---------------------------------------------------------------------
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> >
> >
>
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LeeAnn Pultz
ExtraView Corporation
leeann@extraview.com
831-461-7100 x115 



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