Cc: pgsql-performance@postgresql.org
Content-Type: text/plain; charset="utf-8"
Date: Tue, 25 Sep 2012 08:40:55 -0400
From: "Kevin Grittner" <kgrittn@mail.com>
Message-ID: <20120925124055.241320@gmx.com>
MIME-Version: 1.0
Subject: Re: Postgres becoming slow, only full vacuum fixes it
To: "Kiriakos Tsourapas" <ktsour@gmail.com>,"Mark Kirkwood"
	<mark.kirkwood@catalyst.net.nz>
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Kiriakos Tsourapas wrote:

> When the problem appears, vacuuming is not helping. I ran vacuum
> manually and the problem was still there. Only full vacuum worked.
> 
> As far as I have understood, autovacuuming is NOT doing FULL
> vacuum. So, messing around with its values should not help me in
> any way.

That is absolutely wrong.  A regular vacuum, or autovacuum not
hopelessly crippled by your configuration, will prevent the table
bloat which is slowing things down.  It does not, however, fix bloat
once it has occurred; a normal vacuum then is like closing the barn
door after the horse has already bolted -- it would have prevented
the problem if done in time, but it won't cure it.

A VACUUM FULL in version 8.4 will fix bloat of the table's heap, but
will tend to bloat the indexes.  You should probably fix your
autovcauum configuration (making it *at least* as aggressive as the
default), CLUSTER the affected table(s) to fix both table and index
bloat, and schedule an upgrade to the latest bug fix release of major
version 8.4.

http://www.postgresql.org/support/versioning/

Minor releases (where the version number only changes after the
second dot) only contain fixes for bugs and security problems, and
never require a dump/load or pg_upgrade run.  If you insist on
running with known bugs, you can expect problems.

-Kevin