From: Liviu Ionescu <ilgb@livius.net>
To: pgsql-performance@postgresql.org
Subject: Re: performance drop on 8.2.4, reverting to 8.1.4
Date: Fri, 18 May 2007 14:51:42 +0300
Message-ID: <008901c79942$e7136e10$653e10ac@ilgvaio> (raw)
In-Reply-To: <20070518111455.GA13978@uio.no>
> This seems to be the source of the misestimation. You might
> want to try using "n WHERE n.nodein NOT IN (SELECT nodeid
> FROM templates)" instead of "n LEFT JOIN templates USING
> (nodeid) WHERE templates.nodeid IS NULL" and see if it helps.
it helped, the new version of the query takes 2303 ms on both 8.1.4 and 8.2.4.
any idea why the 8.2.4 planner is not happy with the initial select? was it just a big chance that it worked in 8.1.4 or the 8.2.4 planner has a problem?
or, from another perspective, is the new syntax more portable? what are the chances that after upgrading to 8.3.x to encounter new problems?
regards,
Liviu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: ilgb@livius.net
Subject: Re: performance drop on 8.2.4, reverting to 8.1.4
In-Reply-To: <008901c79942$e7136e10$653e10ac@ilgvaio>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox