Received: from localhost (unknown [200.46.204.183]) by developer.postgresql.org (Postfix) with ESMTP id BEFC92E0060 for ; Wed, 21 May 2008 10:09:57 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 92262-08 for ; Wed, 21 May 2008 10:09:48 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from pih-relay06.plus.net (pih-relay06.plus.net [212.159.14.133]) by developer.postgresql.org (Postfix) with ESMTP id 8DD1E2E005B for ; Wed, 21 May 2008 10:09:52 -0300 (ADT) Received: from [84.51.143.99] (helo=server3.office.archonet.com) by pih-relay06.plus.net with esmtp (Exim) id 1Jyo4j-0003Lv-H5; Wed, 21 May 2008 14:09:50 +0100 Received: from [192.168.1.36] (dell36.office.archonet.com [192.168.1.36]) by server3.office.archonet.com (Postfix) with ESMTP id D075C274063; Wed, 21 May 2008 14:09:48 +0100 (BST) Message-ID: <48341F1D.3090304@archonet.com> Date: Wed, 21 May 2008 14:09:49 +0100 From: Richard Huxton User-Agent: Thunderbird 2.0.0.14 (X11/20080421) MIME-Version: 1.0 To: Luke Lonergan CC: albert@sedifa.com, pgsql-performance@postgresql.org Subject: Re: Posible planner improvement? References: <014F2941B0A1EA47BD61D21526B806E90162C3D2@MI8NYCMAIL08.Mi8.com> In-Reply-To: <014F2941B0A1EA47BD61D21526B806E90162C3D2@MI8NYCMAIL08.Mi8.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Plusnet-Relay: af0580f7500b9cbd0ffbcb66c337ff03 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200805/293 X-Sequence-Number: 30261 Luke Lonergan wrote: > The problem is that the implied join predicate is not being > propagated. This is definitely a planner deficiency. IIRC only equality conditions are propagated and gt, lt, between aren't. I seem to remember that the argument given was that the cost of checking for the ability to propagate was too high for the frequency when it ocurred. Of course, what was true for code and machines of 5 years ago might not be so today. -- Richard Huxton Archonet Ltd