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Re: check point segments leakage ?

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Gaetano Mendola <mendola(at)bigfoot(dot)com>
Cc: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>,"pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: check point segments leakage ?
Date: 2004-07-21 16:32:22
Message-ID: 40FE9A96.5020202@zeut.net (view raw or flat)
Thread:
Lists: pgsql-hackers
Gaetano Mendola wrote:
> I'm pretty sure, see the attached graph. Each morning at 7 a script stop
> the autovacuum, vacuum full the database and reindex the eavy updated 
> tables
> and restart of course the autovacuum. Note also that for all the day I 
> didn't
> have the usual disk usage increment.

I don't know why the 1st VACUUM FULL wasn't able to reclaim the same 
amount of space as the 2nd one, but I would guess that it wasn't able to 
get a lock on some table.  It could have been autovac if it was doing a 
vacuum at that moment, but it could have been something else too.

 From the attached graph, it looks like your stead state database size 
is approx 3.0G.  After the 2nd VACUUM FULL, you dropped to 2.5G, but as 
you can see it's creeping up back up again.

If you let it continue to run without running VACUUM FULL, but with 
autovacuum enabled, and it climbs to 3.0G and stops growing, then I 
think you are fine and you don't need to run VACUUM FULL at all.  If it 
continues to grop witout bound, then you need to up your FSM and/or make 
autovac more aggressive.

Bottom line, you shouldn't need VACUUM FULL, if you do, I think there 
are people on this list that would like to hear about it.

Matthew


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Subject: Re: check point segments leakage ?
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