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Message-ID: <472B5BF7.5080708@altiria.com>
Date: Fri, 02 Nov 2007 18:18:47 +0100
From: =?ISO-8859-1?Q?Diego_Rodr=EDguez_Mart=EDn?=
 <drodriguez@altiria.com>
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To: Tomcat Users List <users@tomcat.apache.org>
Subject: Re: What do I do with a heap dump? (OOM Permgen)
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Hi,

    I found a memory leak in commons pool version 1.3 that is affecting 
tomcat 6.0.x as it is the commons pool library embedded in it. I tried a 
workaround using a factory with commons 1.2, but it also showed a memory 
leak.

    http://www.mail-archive.com/users@tomcat.apache.org/msg29820.html
  
    As far as I know, it has not been resolved, so you could be running 
into this

    Diego


Greg Vilardi escribi�:
> On 2 Nov 2007 at 7:24, Caldarale, Charles R wrote:
>
>   
>>> From: Peter Crowther [mailto:Peter.Crowther@melandra.com] 
>>> 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
>   

-- 
-------------------------------------------------------------
Diego Rodr�guez Mart�n (drodriguez@altiria.com)
ALTIRIA TIC - Servicios SMS - Desarrollo Web
Tel. +34 913311198 - Fax +34 915713993 - M�vil +34 610299750
www.altiria.com
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