Re: VACUUM not doing its job?

From: Joe Conway <mail(at)joeconway(dot)com>
To: Kristian Eide <kreide(at)online(dot)no>
Cc: Ken Corey <ken(at)kencorey(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: VACUUM not doing its job?
Date: 2002-08-04 00:32:52
Message-ID: 3D4C7634.5050105@joeconway.com
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Kristian Eide wrote:
> Thanks, very helpful, although there does not seem to be much description of
> what the two free space map options in postgresql.conf actually do. Doing a
> VACUUM ANALYZE VERBOSE on my largest table gives me:
>
> NOTICE: Pages 43681: Changed 208, Empty 0; Tup 1921387: Vac 61669, Keep 0,
> UnUsed 1362341.
>
> I will try to increase the 'max_fsm_pages' option from 10000 to 500000 and
> see if that helps.
>

Note that you'll need to do a vacuum full *first* to recover the lost
space, since the free space map is populated as the tuples are actually
freed, I believe. After that you can adjust 'max_fsm_pages' and your
vacuum frequency to achieve an equilibrium.

Joe

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