Received: from localhost (maia-3.hub.org [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 4C80E9FB7D1 for ; Wed, 20 Jun 2007 02:43:57 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 06686-04 for ; Wed, 20 Jun 2007 02:43:51 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id E1AB59FB7E1 for ; Wed, 20 Jun 2007 02:43:52 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l5K5ho0s007622; Wed, 20 Jun 2007 01:43:50 -0400 (EDT) To: Greg Smith cc: pgsql-performance@postgresql.org Subject: Re: Volunteer to build a configuration tool In-reply-to: References: <1182298719.4482.133.camel@ipso.snappymail.ca> Comments: In-reply-to Greg Smith message dated "Wed, 20 Jun 2007 01:03:19 -0400" Date: Wed, 20 Jun 2007 01:43:50 -0400 Message-ID: <7621.1182318230@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200706/402 X-Sequence-Number: 25435 Greg Smith writes: > On Wed, 20 Jun 2007, Mike Benoit wrote: >> I don't think something like this would be very difficult at all to >> write > Here I just smile and say that proves you've never tried to write one :) I'm with Greg on this. It's not that easy to optimize in a multi-parameter space even if all conditions are favorable, and they never are. I think what would be much more useful in the long run is some serious study of the parameters themselves. For instance, random_page_cost is a self-admitted oversimplification of reality. We know that good settings for it depend critically on how large your DB is relative to your RAM; which means there are at least two parameters there, but no one's done any serious thinking about how to disentangle 'em. regards, tom lane