Re: Interpreting vacuum verbosity

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Ed L(dot)" <pgsql(at)bluepolka(dot)net>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: Interpreting vacuum verbosity
Date: 2004-05-07 17:25:14
Message-ID: 14232.1083950714@sss.pgh.pa.us
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"Ed L." <pgsql(at)bluepolka(dot)net> writes:
> No, our autovac logs the number of changes (upd+del for vac, upd+ins+del for
> analyze) on each round of checks, and we can see it was routinely
> performing when expected. The number of updates/deletes just far exceeded
> the thresholds. Vac threshold was 2000, and at times there might be
> 300,000 outstanding changes in the 10-30 minutes between vacuums.

Well, in that case you probably want a lot less than "10-30 minutes"
between vacuums, at least for this particular table. I don't know how
one configures autovac for this, but I suppose it can be done ...

> max_fsm_relations = 1000 and max_fsm_pages = 10000.

Also you doubtless need max_fsm_pages a lot higher than that. A
conservative setting would make it as big as your whole database,
eg for a 10Gb disk footprint use 10Gb/8K (something upwards of
a million) FSM page slots.

regards, tom lane

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