From: thomas at tada.se (Thomas Hallgren)
Date: Tue, 27 Jun 2006 16:03:05 +0200
Subject: [Pljava-dev] java.lang.OutOfMemoryError
In-Reply-To: <44A134C6.5030003@insa-toulouse.fr>
References: <4492740D.4040302@insa-toulouse.fr> <4492BB01.5060205@tada.se>
	<44965774.7050203@insa-toulouse.fr> <44966070.4040806@tada.se>
	<44A134C6.5030003@insa-toulouse.fr>
Message-ID: <44A13A99.60406@tada.se>

Hi Eric,
I just CC'd you on a mail that I posted to the PostgreSQL hackers list 
concerning your 'buffer refcount leak'. I'm not sure that's the cause of 
your problems though. I need to know more about what you actually do 
during your 'long treatment'. Some operations might be very memory 
consuming. You're OK with -Xmx512M you say. Have you been able to figure 
out where the upper bound is? What happens with -Xmx256M, -Xmx128M, etc.?

Are you doing a lot of XML processing? Do you have code that reuses a 
lot of class loaders over and over again (might run out of perm-gen space).

Regards,
Thomas Hallgren

Eric BOYER wrote:
> Hello,
>
> we use now pljava 1.3 and postgres 8.1.4
> we can't use java 1.5 because it depends on xmlrpc 3 which is an alpha
> version.
>
> The problem is still there.
>
> We have a big treatment and after a long time, we have this outOfMemory.
> We print the warning on the statement :
> ERROR - ====>org.postgresql.pljava.internal.ServerException:
> java.lang.OutOfMemoryErrorjava.lang.OutOfMemoryError
> INFO - Statement WarningWARNING: buffer refcount leak: [779]
> (rel=1663/16440/52989, blockNum=3, flags=0x27, refcount=1 2)
>
> What could be this buffer refcount leak.
>
> Is the "buffer refcount leak" the cause of the OufOfMemoryError or its 
> consequence ?
>
> This long treatment is OK if we have the option : -Xmx512M
> If we use -Xmx8M, it crash more quickly !
>
> Thanks for your help
>
> Eric
>
>
>
> Thomas Hallgren a ?crit :
>
>> Eric BOYER wrote:
>>
>>> Thomas Hallgren a ?crit :
>>>
>>>> Eric,
>>>> You limit the postmaster to use 64M memory per session.
>>>>
>>> A session is a the trigger ?
>>>
>> No, a session is a connection to the database.
>>
>>> We use :
>>> Postgres 8.1
>>> Pljava 1.2.0
>>> jdk 1.4
>>>
>>> Our server launch trigger which launch trigger, etc ...
>>> The treatment is long sometimes ...
>>>
>> I would recommend three things.
>>
>> 1. Upgrade your Java to a 1.5.0_07 version. It performs much better 
>> from a memory consumption perspective.
>> 2. Updgrate to PL/Java 1.3.0
>> 3. If that doesn't help, try -Xmx128M.
>>
>> Regards,
>> Thomas Hallgren
>>
>
>