X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id 6643D5372B for ; Thu, 28 Jul 2005 18:54:28 -0300 (ADT) Received: from svr1.postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 07598-02 for ; Thu, 28 Jul 2005 21:54:27 +0000 (GMT) Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by svr1.postgresql.org (Postfix) with ESMTP id 668A7537AD for ; Thu, 28 Jul 2005 18:54:19 -0300 (ADT) X-EthosMedia-Virus-Scanned: no infections found Received: from [64.81.245.111] (account josh@agliodbs.com HELO temoku.sf.agliodbs.com) by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 7666796; Thu, 28 Jul 2005 14:56:34 -0700 From: Josh Berkus Reply-To: josh@agliodbs.com Organization: Aglio Database Solutions To: Greg Stark Subject: Re: wal_buffer tests in Date: Thu, 28 Jul 2005 14:57:10 -0700 User-Agent: KMail/1.8 Cc: pgsql-hackers@postgresql.org References: <200507271330.02083.josh@agliodbs.com> <87oe8n881i.fsf@stark.xeocode.com> In-Reply-To: <87oe8n881i.fsf@stark.xeocode.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200507281457.10637.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.049 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO X-Spam-Level: X-Archive-Number: 200507/1061 X-Sequence-Number: 71113 Greg, > You have wal_buffer set to 2048? That's pretty radical compared to the > default of just 5. Your tests shows you had to go to this large a value > to see the maximum effect? No, take a look at the graph. It looks like we got the maximum effect from a wal_buffers somewhere between 64 and 256. On the DBT2 runs, any variation less than 5% is just noise. -- --Josh Josh Berkus Aglio Database Solutions San Francisco