Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id E70F69FB772 for ; Thu, 12 Jul 2007 02:15:49 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 85337-07 for ; Thu, 12 Jul 2007 02:15:04 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.177]) by postgresql.org (Postfix) with ESMTP id 06CD49FB827 for ; Thu, 12 Jul 2007 02:06:36 -0300 (ADT) Received: from [194.25.154.138] (helo=webserv.wug.de) by mrelayeu.kundenserver.de (node=mrelayeu4) with ESMTP (Nemesis), id 0ML21M-1I8qsq1sWA-0000ue; Thu, 12 Jul 2007 07:06:32 +0200 Received: from kretschmer by webserv.wug.de with local (Exim 3.36 #1) id 1I8qsp-0000lI-00 for pgsql-performance@postgresql.org; Thu, 12 Jul 2007 07:06:31 +0200 Date: Thu, 12 Jul 2007 07:06:31 +0200 From: "A. Kretschmer" To: pgsql-performance@postgresql.org Subject: Re: bitmap-index-scan slower than normal index scan Message-ID: <20070712050631.GA2729@a-kretschmer.de> References: <20070711183638.GA30872@KanotixBox> <1331.1184184273@sss.pgh.pa.us> <20070711201958.GA18449@KanotixBox> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070711201958.GA18449@KanotixBox> X-OS: Debian/GNU Linux - weil ich es mir Wert bin! X-Message-Flag: "Windows" is not the answer. "Windows" is the question and the answer is "no"! User-Agent: Mutt/1.5.9i X-Provags-ID: V01U2FsdGVkX18qQsAgDwRnEqfL5qn3d2MMENpotD8rmMfjzW8 dcCp3a0ju1ja8Zl320bAmxk9xS/+Q+vk4QPc41lJhTgBKUWhKT U6K8lV9krLWSZ5XkBE3XJrzB6yGGeIp X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/131 X-Sequence-Number: 25815 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