[pgpool-general: 109] Re: severe memory leak in 3.1.1

Tatsuo Ishii ishii at postgresql.org
Thu Dec 22 06:46:54 JST 2011


> On Wed, Dec 21, 2011 at 7:39 AM, Tatsuo Ishii <ishii at postgresql.org> wrote:
>>> Greetings,
>>> I'm running pgpool-3.1.1 on a Linux-x86_64 system with 8GB RAM and
>>> 2.5GB swap.  Ever since we upgraded from pgpool-3.0.3 to 3.0.4, we've
>>> seen a severe memory leak which consistently consumes all the RAM+swap
>>> on the system every 4-7 days.  The leak is so severe that sometimes
>>> the OOM killer cannot respond fast enough, and the entire server had
>>> locked up one time (with OOM killer spew on the local console).  We're
>>> confident that the leak is in pgpool, as if we stop and (re)start
>>> pgpool, all the memory in use is freed up immediately.
>>>
>>> We were hoping that upgrading to 3.1.1 would eliminate the problem,
>>> however we upgraded to 3.1.1 last Thursday, and as of this morning its
>>> obvious that the leak is still present.  Please advise what kind of
>>> information we can provide to debug this problem.
>>
>> Self contained test case is the best way to tuckle the problem. Can
>> you please provide?
> 
> I'm afraid that I don't know what is causing this.  I'm going to need
> your assistance here.

Please provide pgpool.conf. Also please let know me how did you start
pgpool (pgpool options) and what queries most likely cause the leak. I
need to reproduce your problem.

In the mean time child_life_time or child_max_connections might help
you, because they force pgpool child process to exit periodically thus
free memory allocated by pgpool. If you still see leak, the problem
must be in the pgpool parent process, not child. In this case you can
see the pgpool parent process growing.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp


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