Memory usage of auto-vacuum

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
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