Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 94851635814 for ; Fri, 20 Mar 2009 19:05:27 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 96962-06 for ; Fri, 20 Mar 2009 19:05:18 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from lists.commandprompt.com (host-159.commandprompt.net [207.173.203.159]) by mail.postgresql.org (Postfix) with ESMTP id 6C876635800 for ; Fri, 20 Mar 2009 19:05:24 -0300 (ADT) Received: from perhan.alvh.no-ip.org (200-126-101-194.bk7-dsl.surnet.cl [200.126.101.194]) (authenticated bits=0) by lists.commandprompt.com (8.13.8/8.13.8) with ESMTP id n2KMC25v015862 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 20 Mar 2009 15:12:07 -0700 Received: by perhan.alvh.no-ip.org (Postfix, from userid 1000) id 2A80547CDF; Fri, 20 Mar 2009 18:05:13 -0400 (CLT) Date: Fri, 20 Mar 2009 18:05:13 -0400 From: Alvaro Herrera To: Scott Carey Cc: Robert Haas , "Jignesh K. Shah" , Greg Smith , Kevin Grittner , "pgsql-performance@postgresql.org" Subject: Re: Proposal of tunable fix for scalability of 8.4 Message-ID: <20090320220513.GS8313@alvh.no-ip.org> References: <603c8f070903191349p5e8fb00as2816581d584fcefd@mail.gmail.com> <20090320154601.GC8313@alvh.no-ip.org> <20090320215813.GR8313@alvh.no-ip.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20090320215813.GR8313@alvh.no-ip.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0 (lists.commandprompt.com [207.173.203.159]); Fri, 20 Mar 2009 15:12:07 -0700 (PDT) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200903/308 X-Sequence-Number: 33230 Alvaro Herrera escribió: > So Simon's correct. And perhaps this explains why Jignesh is measuring an improvement on his benchmark. Perhaps an useful experiment would be to turn this behavior off and compare performance. This lack of measurement is probably the cause that the suggested patch to fix it was never applied. The patch is here http://archives.postgresql.org//pgsql-hackers/2004-11/msg00935.php -- Alvaro Herrera http://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc.