Received: from localhost (unknown [200.46.204.191]) by postgresql.org (Postfix) with ESMTP id 633429F9833 for ; Sat, 1 Sep 2007 07:40:29 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.191]) (amavisd-maia, port 10024) with ESMTP id 85852-05 for ; Sat, 1 Sep 2007 07:40:23 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from mail.metronet.co.uk (mail.metronet.co.uk [213.162.97.75]) by postgresql.org (Postfix) with ESMTP id C1F9C9F9830 for ; Sat, 1 Sep 2007 07:40:23 -0300 (ADT) Received: from server3.office.archonet.com (84-51-143-99.archon037.adsl.metronet.co.uk [84.51.143.99]) by smtp.metronet.co.uk (MetroNet Mail) with ESMTP id A5C681451BC; Sat, 1 Sep 2007 11:29:34 +0100 (BST) Received: from [192.168.1.36] (dell36.office.archonet.com [192.168.1.36]) by server3.office.archonet.com (Postfix) with ESMTP id 6867C27405F; Sat, 1 Sep 2007 11:29:34 +0100 (BST) Message-ID: <46D93F0E.5070404@archonet.com> Date: Sat, 01 Sep 2007 11:29:34 +0100 From: Richard Huxton User-Agent: Thunderbird 2.0.0.0 (X11/20070326) MIME-Version: 1.0 To: Richard Ray Cc: pgsql-sql@postgresql.org Subject: Re: How to influence the planner References: <373D2F52-E9CD-485A-9BF1-B019349FA5EC@seespotcode.net> <2005.1188596277@sss.pgh.pa.us> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200709/1 X-Sequence-Number: 29214 Richard Ray wrote: > > When is enable_seqscan = off appropriate Never(*) It's not for normal usage, the various enable_xxx settings do let you experiment with different options if you think the planner is making a mistake. (*) OK, sooner or later, if you have enough systems and enough performance-critical queries then you might want to use it in production. But only if you really know what you're doing and you've exhausted you're other options. -- Richard Huxton Archonet Ltd