From: A. Kretschmer <andreas.kretschmer@schollglas.com>
To: pgsql-performance@postgresql.org
Subject: Re: bitmap-index-scan slower than normal index scan
Date: Thu, 12 Jul 2007 07:06:31 +0200
Message-ID: <20070712050631.GA2729@a-kretschmer.de> (raw)
In-Reply-To: <20070711201958.GA18449@KanotixBox>
References: <20070711183638.GA30872@KanotixBox>
<1331.1184184273@sss.pgh.pa.us>
<20070711201958.GA18449@KanotixBox>
am Wed, dem 11.07.2007, um 22:19:58 +0200 mailte Andreas Kretschmer folgendes:
> > Also, part of the problem here looks to be an overestimate of the number
> > of rows matching ab = 347735. It might help to increase the statistics
> > target for that column.
>
> I will try this tomorrow and inform you about the result. I've never
> done this before, i need to read the docs about this.
Okay, done, setting to 100 (thanks to mastermind) and now i got an Index
Scan using idx_ab with a total runtime: 0.330 ms.
Great, thanks. And yes, i will update soon...
Andreas
--
Andreas Kretschmer
Kontakt: Heynitz: 035242/47150, D1: 0160/7141639 (mehr: -> Header)
GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net
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: andreas.kretschmer@schollglas.com
Subject: Re: bitmap-index-scan slower than normal index scan
In-Reply-To: <20070712050631.GA2729@a-kretschmer.de>
* 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