Date: Tue, 8 May 2007 18:21:02 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: pgsql-performance@postgresql.org
Subject: Re: What's The Difference Between VACUUM and VACUUM ANALYZE?
Message-ID: <20070508222102.GD24167@alvh.no-ip.org>
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	<20070508215213.GC24167@alvh.no-ip.org>
	<20070508220608.GA8457@uio.no>
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Steinar H. Gunderson wrote:
> On Tue, May 08, 2007 at 05:52:13PM -0400, Alvaro Herrera wrote:
> >> I am trying to follow a message thread. One guy says we should be running
> >> vacuum analyze daily and the other says we should be running vacuum multiple
> >> times a day. I have tried looking for what a vacuum analyze is to help me
> >> understand but no luck.
> > VACUUM ANALYZE is like VACUUM, except that it also runs an ANALYZE
> > afterwards.
> 
> Shoot me if I'm wrong here, but doesn't VACUUM ANALYZE check _all_ tuples,
> as compared to the random selection employed by ANALYZE?

You are wrong, but it won't be me the one to shoot you.

There have been noises towards making the ANALYZE portion use the same
scan that VACUUM already does, but nobody has written the code (it would
be useful for some kinds of stats).

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support