X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (unknown [200.46.204.144]) by svr1.postgresql.org (Postfix) with ESMTP id B102452835 for ; Wed, 6 Jul 2005 21:37:57 -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 23028-02 for ; Thu, 7 Jul 2005 00:37:55 +0000 (GMT) Received: from davinci.ethosmedia.com (server227.ethosmedia.com [209.128.84.227]) by svr1.postgresql.org (Postfix) with ESMTP id 1094652808 for ; Wed, 6 Jul 2005 21:37:54 -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 7579489; Wed, 06 Jul 2005 17:40:05 -0700 From: Josh Berkus Reply-To: josh@agliodbs.com Organization: Aglio Database Solutions To: paul@oxton.com Subject: Re: Data Warehousing Tuning Date: Wed, 6 Jul 2005 17:40:12 -0700 User-Agent: KMail/1.8 Cc: pgsql-performance@postgresql.org References: <3688.217.45.209.171.1120670147.squirrel@www.gradwell.com> In-Reply-To: <3688.217.45.209.171.1120670147.squirrel@www.gradwell.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200507061740.12875.josh@agliodbs.com> X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, hits=0.045 tagged_above=0 required=5 tests=AWL, FORGED_RCVD_HELO X-Spam-Level: X-Archive-Number: 200507/57 X-Sequence-Number: 13298 Paul, > Has anyone experienced real performance gains by moving the pg_xlog > files? Yes. Both for data load and on OLTP workloads, this increased write performance by as much as 15%. However, you need to configure the xlog drive correctly, you can't just move it to a new disk. Make sure the other disk is dedicated exclusively to the xlog, set it forcedirectio, and increase your checkpoint_segments to something like 128. -- --Josh Josh Berkus Aglio Database Solutions San Francisco