To: Steve Wampler <swampler@noao.edu>
cc: Postgres-performance <pgsql-performance@postgresql.org>
Subject: Re: Help speeding up delete 
In-reply-to: <43790A99.9050603@noao.edu> 
References: <43790A99.9050603@noao.edu>
Comments: In-reply-to Steve Wampler <swampler@noao.edu>
	message dated "Mon, 14 Nov 2005 15:07:21 -0700"
Date: Mon, 14 Nov 2005 18:42:43 -0500
Message-ID: <4162.1132011763@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

Steve Wampler <swampler@noao.edu> writes:
> We've got an older system in production (PG 7.2.4).  Recently
> one of the users has wanted to implement a selective delete,
> but is finding that the time it appears to take exceeds her
> patience factor by several orders of magnitude.  Here's
> a synopsis of her report.  It appears that the "WHERE
> id IN ..." is resulting in a seq scan that is causing
> the problem, but we're not SQL expert enough to know
> what to do about it.

> Can someone point out what we're doing wrong, or how we
> could get a (much) faster delete?  Thanks!

Update to 7.4 or later ;-)

Quite seriously, if you're still using 7.2.4 for production purposes
you could justifiably be accused of negligence.  There are three or four
data-loss-grade bugs fixed in the later 7.2.x releases, not to mention
security holes; and that was before we abandoned support for 7.2.
You *really* need to be thinking about an update.

			regards, tom lane