To: pgsql-performance@postgresql.org
From: Miernik <public@public.miernik.name>
Subject: Re: Database size Vs performance degradation
Date: Wed, 30 Jul 2008 23:58:34 +0200
Lines: 19
Message-ID: <20080730215834.5323.0.NOFFLE@turbacz.local>
References: 
 <35FABCF85D99464FB00BC5123DC2A70A051D0FB8@s228130hz1ew09.apptix-01.savvis.net>
	<276541.4189.qm@web25805.mail.ukl.yahoo.com>
Reply-To: Miernik <public@public.miernik.name>
User-Agent: tin/1.9.3-20080506 ("Dalintober") (UNIX) (Linux/2.6.25-2-686
	(i686))

Valentin Bogdanov <valiouk@yahoo.co.uk> wrote:
> I am guessing that you are using DELETE to remove the 75,000
> unimportant.  Change your batch job to CREATE a new table consisting
> only of the 5,000 important. You can use "CREATE TABLE table_name AS
> select_statement" command. Then drop the old table. After that you can
> use ALTER TABLE to change the name of the new table to that of the old
> one.

I have a similar, but different situation, where I TRUNCATE a table with
60k rows every hour, and refill it with new rows. Would it be better
(concerning bloat) to just DROP the table every hour, and recreate it,
then to TRUNCATE it? Or does TRUNCATE take care of the boat as good as a
DROP and CREATE?

I am running 8.3.3 in a 48 MB RAM Xen, so performance matters much.

-- 
Miernik
http://miernik.name/