Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id 9C1649FB38E for ; Sat, 23 Jun 2007 16:28:22 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.182]) (amavisd-maia, port 10024) with ESMTP id 53640-07 for ; Sat, 23 Jun 2007 16:28:16 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from westnet.com (westnet.com [216.187.52.2]) by postgresql.org (Postfix) with ESMTP id A61679FB366 for ; Sat, 23 Jun 2007 16:28:18 -0300 (ADT) Received: from westnet.com (localhost [127.0.0.1]) by westnet.com (8.14.0/8.14.0) with ESMTP id l5NJSIfR001900 for ; Sat, 23 Jun 2007 15:28:18 -0400 (EDT) Received: from localhost (gsmith@localhost) by westnet.com (8.14.0/8.13.2/Submit) with ESMTP id l5NJSI28001897 for ; Sat, 23 Jun 2007 15:28:18 -0400 (EDT) X-Authentication-Warning: westnet.com: gsmith owned process doing -bs Date: Sat, 23 Jun 2007 15:28:17 -0400 (EDT) From: Greg Smith X-X-Sender: gsmith@westnet.com To: pgsql-performance@postgresql.org Subject: Re: Volunteer to build a configuration tool In-Reply-To: Message-ID: References: <1182298719.4482.133.camel@ipso.snappymail.ca> <7621.1182318230@sss.pgh.pa.us> <9001.1182323187@sss.pgh.pa.us> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200706/554 X-Sequence-Number: 25587 On Thu, 21 Jun 2007, Campbell, Lance wrote: > I have a PostgreSQL database that runs on a dedicated server. The > server has 24Gig of memory. What would be the max size I would ever > want to set the shared_buffers to if I where to relying on the OS for > disk caching approach? It seems that no matter how big your dedicated > server is there would be a top limit to the size of shared_buffers. It's impossible to say exactly what would work optimally in this sort of situation. The normal range is 25-50% of total memory, but there's no hard reason for that balance; for all we know your apps might work best with 20GB in shared_buffers and only a relatively small 4GB left over for the rest of the OS to use. Push it way up and and see what you get. This is part of why the idea of an "advanced" mode for this tool is suspect. Advanced tuning usually requires benchmarking with as close to real application data as you can get in order to make good forward progress. -- * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD