X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 028989DD807 for ; Fri, 10 Feb 2006 21:54:01 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 63973-01-5 for ; Fri, 10 Feb 2006 21:54:03 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from cassarossa.samfundet.no (cassarossa.samfundet.no [129.241.93.19]) by postgresql.org (Postfix) with ESMTP id 58FDE9DD940 for ; Fri, 10 Feb 2006 21:51:59 -0400 (AST) Received: from trofast.ipv6.sesse.net ([2001:700:300:dc03:20e:cff:fe36:a766] helo=trofast.sesse.net) by cassarossa.samfundet.no with esmtp (Exim 4.50) id 1F7jve-0007J4-5F; Sat, 11 Feb 2006 02:52:02 +0100 Received: from sesse by trofast.sesse.net with local (Exim 3.36 #1 (Debian)) id 1F7jvi-00057C-00; Sat, 11 Feb 2006 02:52:06 +0100 Date: Sat, 11 Feb 2006 02:52:06 +0100 From: "Steinar H. Gunderson" To: uwcssa Cc: pgsql-performance@postgresql.org Subject: Re: postgresql geqo optimization Message-ID: <20060211015206.GA19612@uio.no> Mail-Followup-To: uwcssa , pgsql-performance@postgresql.org References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Operating-System: Linux 2.6.14.3 on a x86_64 X-Message-Flag: Outlook? --> http://www.mozilla.org/products/thunderbird/ User-Agent: Mutt/1.5.11 X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.077 required=5 tests=[AWL=0.077] X-Spam-Score: 0.077 X-Spam-Level: X-Archive-Number: 200602/128 X-Sequence-Number: 17114 On Fri, Feb 10, 2006 at 08:46:14PM -0500, uwcssa wrote: > I am wondering if anyone here ever had complex queries that the GEQO fails > to work properly, i.e., finds a terrible query plan as compared to one > found by DP optimizer (by forcing Postgresql always uses DP). This is > important to me since I am trying to see what type of queries will be worth > spending a lot of time doing a thorough DP optimization (if it is going to > be executed again and again). There have been a few problems earlier on this list which might have been the geqo's fault; search the list archives for "geqo" or "genetic", and you should be able to find them quite easily. /* Steinar */ -- Homepage: http://www.sesse.net/