Received: from localhost (maia-5.hub.org [200.46.204.182]) by postgresql.org (Postfix) with ESMTP id A1CE69FB9DD for ; Mon, 11 Jun 2007 12:35:07 -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 96958-03 for ; Mon, 11 Jun 2007 12:34:20 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from main2.mycybernet.net (main2.mycybernet.net [209.222.63.140]) by postgresql.org (Postfix) with ESMTP id EF2F19FA617 for ; Mon, 11 Jun 2007 12:34:20 -0300 (ADT) Received: from 227-54-222-209.mycybernet.net ([209.222.54.227] helo=phlogiston.dydns.org) by main2.mycybernet.net with esmtp (Exim 4.62) (envelope-from ) id 1HxluO-00081M-9m for pgsql-performance@postgresql.org; Mon, 11 Jun 2007 11:34:20 -0400 Received: by phlogiston.dydns.org (Postfix, from userid 1000) id DC078404E; Mon, 11 Jun 2007 11:34:14 -0400 (EDT) Date: Mon, 11 Jun 2007 11:34:14 -0400 From: Andrew Sullivan To: pgsql-performance@postgresql.org Subject: Re: How much ram is too much Message-ID: <20070611153414.GK24327@phlogiston.dyndns.org> References: <47A154B5-496C-478A-B60D-4238AF12EAC6@fastcrypt.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200706/187 X-Sequence-Number: 25220 On Mon, Jun 11, 2007 at 11:09:42AM -0400, Dave Cramer wrote: > >and set them to anything remotely close to 128GB. > > Well, we'd give 25% of it to postgres, and the rest to the OS. Are you quite sure that PostgreSQL's management of the buffers is efficient with such a large one? In the past, that wasn't the case for relatively small buffers; with the replacement of single-pass LRU, that has certainly changed, but I'd be surprised if anyone tested a buffer as large as 32G. A -- Andrew Sullivan | ajs@crankycanuck.ca The whole tendency of modern prose is away from concreteness. --George Orwell