Received: from localhost (unknown [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 539272E02FF for ; Wed, 12 Dec 2007 07:48:53 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 70177-02 for ; Wed, 12 Dec 2007 07:48:43 -0400 (AST) Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id 7EA192E02AE for ; Wed, 12 Dec 2007 07:48:49 -0400 (AST) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id lBCBmmEL018040; Wed, 12 Dec 2007 06:48:48 -0500 (EST) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id lBCBmmFZ018037; Wed, 12 Dec 2007 06:48:48 -0500 (EST) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Wed, 12 Dec 2007 06:48:48 -0500 (EST) From: Greg Smith X-X-Sender: gsmith@westnet.com To: Matthew Lunnon cc: pgsql-performance@postgresql.org Subject: Re: Limited performance on multi core server In-Reply-To: <475FB50B.8060701@rwa-net.co.uk> Message-ID: References: <475FB50B.8060701@rwa-net.co.uk> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200712/170 X-Sequence-Number: 27986 On Wed, 12 Dec 2007, Matthew Lunnon wrote: > I have a 4 * dual core 64bit AMD OPTERON server with 16G of RAM, running > postgres 7.4.3. > shared_buffers = 96000 As you've already been told repeatedly 7.4 is a release from long before optimizations to work well on a multi-core server like this. I'll only add that because of those problems, larger values of shared_buffers were sometimes counter-productive with these old versions. You should try reducing that to the 10,000-50000 range and see if things improve; that's the general range that was effective with 7.4. Continue to set effective_cache_size to a large value so that the optimizer knows how much RAM is really available. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD