Re: Still confused about VACUUM vs. VACUUM FULL

From: Jeff Boes <jboes(at)nexcerpt(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-admin(at)postgresql(dot)org
Subject: Re: Still confused about VACUUM vs. VACUUM FULL
Date: 2003-06-12 16:53:03
Message-ID: 1055436783.27087.38.camel@takin.private.nexcerpt.com
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On Thu, 2003-06-12 at 12:42, Tom Lane wrote:
> Jeff Boes <jboes(at)nexcerpt(dot)com> writes:
> > For large (>1 million rows) tables
> > which have a pretty high turn-over (average life span of a row is 3
> > days), should there be any query performance differences whether you
> > VACUUM FULL or not?
>
> How often do you VACUUM? Do you have enough FSM space to support the
> number of pages that get dirtied between vacuums? If you don't, the
> physical table size will bloat over time, leading to progressive
> slowdown.
>

We've gone from daily, to twice daily, to several times during the "peak
updates" period, and back to twice daily.

We're also ANALYZE-ing the largest 12-18 tables on a cycle: every twenty
minutes, a daemon wakes up and ANALYZEs until they're all done or two
minutes has elapsed, whichever comes first.

max_fsm_relations = 200
max_fsm_pages = 350000

We have around 220 tables total, only 40 of which have more than 1000
pg_class.reltuples.

--
Jeff Boes vox 269.226.9550 ext 24
Database Engineer fax 269.349.9076
Nexcerpt, Inc. http://www.nexcerpt.com
...Nexcerpt... Extend your Expertise

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