From: Gael Le Mignot <gael@pilotsystems.net>
To: pgsql-performance@postgresql.org
Subject: Memory usage of auto-vacuum
Organization: Pilot Systems
Mail-Copies-To: nobody
Date: Sat, 09 Jul 2011 09:25:32 +0200
Message-ID: <plop87tyavncer.fsf@aoskar.kilobug.org>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit


Hello,

We are running  a PostgreSQL 8.4 database, with  two tables containing a
lot (> 1 million) moderatly  small rows. It contains some btree indexes,
and one of the two tables contains a gin full-text index.

We noticed  that the  autovacuum process  tend to use  a lot  of memory,
bumping the postgres process near 1Gb while it's running.

I looked in  the documentations, but I didn't find  the information : do
you know  how to estimate the  memory required for the  autovacuum if we
increase the number of rows ? Is it linear ? Logarithmic ? 

Also, is  there a way  to reduce that  memory usage ? Would  running the
autovacuum more frequently lower its memory usage ?

Regards,

-- 
Gaël Le Mignot - gael@pilotsystems.net
Pilot Systems - 9, rue Desargues - 75011 Paris
Tel : +33 1 44 53 05 55 - www.pilotsystems.net
Gérez vos contacts et vos newsletters : www.cockpit-mailing.com