Date: Mon, 4 Jun 2007 10:49:06 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: "Charles.Hou" <ivan.hou@msa.hinet.net>
Cc: pgsql-admin@postgresql.org
Subject: Re: Auto Vacuum question?
Message-ID: <20070604144906.GH4779@alvh.no-ip.org>
References: <1180966368.172224.250500@x35g2000prf.googlegroups.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1180966368.172224.250500@x35g2000prf.googlegroups.com>
User-Agent: Mutt/1.5.13 (2006-08-11)

Charles.Hou wrote:
> i set the auto vacuum option to enable. but my database size(hard-
> disk
> space) still increased from 420MB to 440MB in 8 hours. most of the
> operations in this database are the "Select" query command, just few
> of "Update or Insert".
> why it can be increased so strongly?
> after i executed the command " vaccumdb -f -z testdb", but the size
> just decreased 1 or 2MB...
> what's the problem?

It is normal that the tables grow a bit to a stationary state of dead
space (generated by UPDATE and DELETE).  However it is not normal if it
loses track of that dead space.  One thing you can and should do is
adjust the autovacuum settings (for example lowering the vacuum scale
factor and threshold values).  Another is to correctly set the FSM
values.

Have you done both?

-- 
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.