On 2 Nov 2007 at 7:24, Caldarale, Charles R wrote:
> > From: Peter Crowther [mailto:[EMAIL PROTECTED]
> > Subject: RE: What do I do with a heap dump? (OOM Permgen)
> >
> > As far as I know, public enemy #1 for eating PermGen space is
> > still developers using the Singleton pattern in their code
> > and not having listeners to null out the singleton instance
> > when the webapp is undeployed.
>
> Analagous use of ThreadLocal is also a subtle contributor to the
> problem. The offending references must be cleared at the end of
> processing of each request, since listeners don't have ready access to
> the thread pool.
Thank you for the pointers Peter. We do not have any Singletons in the
application nor do we use ThreadLocal. However, we do not seem to be
cleaning up the JDBC classes on redeploy. I'll install the
SessionListener code that is mentionned in the references in Peter's
reply. I'm also using the eval version of yourkit now to see what
exactly is attached to each of the 52 WebAppClassLoaders in the dump.
I'll be back if I get stuck again further down the road. Thank you to
all of the people who replied for the pointers and the tool
recommendations.
-Greg
--
Gregory H. Vilardi 631-752-2701x240 [EMAIL PROTECTED]
Project Manager / Lead Software Engineer Fax: (631)752-3397
Recurrent Software Solutions, Inc. http://www.recurrentsoft.com
1 Huntington Quadrangle, Suite 1C02, Melville, NY 11747
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