Received: from localhost (postgresql.org [64.49.215.8]) by postgresql.org (Postfix) with ESMTP id 921DC47610B for ; Fri, 4 Oct 2002 08:10:52 -0400 (EDT) Received: from bob.samurai.com (bob.samurai.com [205.207.28.75]) by postgresql.org (Postfix) with ESMTP id 1385B476061 for ; Fri, 4 Oct 2002 08:10:52 -0400 (EDT) Received: from boston.samurai.com (DU179.N224.ResNet.QueensU.CA [130.15.224.179]) by bob.samurai.com (Postfix) with ESMTP id 4C25D1EDA; Fri, 4 Oct 2002 08:10:54 -0400 (EDT) To: Richard Huxton Cc: Siva Kumar , pgsql-general@postgresql.org Subject: Re: Query optimization References: <200210041347.55055.tech@leatherlink.net> <200210041114.17241.dev@archonet.com> From: Neil Conway In-Reply-To: <200210041114.17241.dev@archonet.com> Date: 04 Oct 2002 08:10:37 -0400 Message-ID: <87adlube0y.fsf@mailbox.samurai.com> Lines: 20 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: by AMaViS new-20020517 X-Archive-Number: 200210/180 X-Sequence-Number: 31178 Richard Huxton writes: > First stage though, run an EXPLAIN and if you need help understanding it post > the output back to the list. Yep, that's a good idea. Another thing to try is to disable GEQO (SET geqo = off;) and see what difference that makes to the performance of the optimizer and the quality of the chosen plan (12 relations is close to the cross-over point for the useability of the genetic optimizer, IME). Also, your comment regarding slow access over the Internet is not a problem with PostgreSQL -- if it really *is* 2x or so slower when done remotely, talk to your network admin. Cheers, Neil -- Neil Conway || PGP Key ID: DB3C29FC