Re: Huge pg_toast table - Mailing list pgsql-general

From Doug McNaught
Subject Re: Huge pg_toast table
Date
Msg-id m3znj3skls.fsf@varsoon.wireboard.com
Whole thread Raw
In response to Huge pg_toast table  ("Ed L." <pgsql@bluepolka.net>)
List pgsql-general
"Ed L." <pgsql@bluepolka.net> writes:

> On Thursday July 24 2003 2:53, Ed L. wrote:
> > I have a frequently updated table called 'audit' with 10,000 rows of
> > about 90kb per row (90kb * 10k = 900mb).  There is a 35gb system table
> > called pg_toast_NNNNN where NNNNN is the oid of the 'audit' table.
> >
> > My question:  should I expect a 'vacuum full' to shrink the size of this
> > pg_toast table?  I ask instead of just doing it because doing so would
> > require scheduling customer downtime since 'vacuum full' blocks access.
>
> BTW, we currently run 'analyze' every 2 hours and vacuum once daily on this
> 7.3.2 cluster....

You might want to check your FSM (free space map) settings--it sounds
like you're losing track of some pages that (non-blocking) vacuum
could salvage, saving you from having to VACUUM FULL.  There's been a
fair amount of discussion about FSM tuning if you check the
archives...

-Doug

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