Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id 79A50B5DC13 for ; Tue, 20 Sep 2011 21:36:55 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 14032-05 for ; Wed, 21 Sep 2011 00:36:48 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0-rc2 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 658A2B5DC33 for ; Tue, 20 Sep 2011 21:36:42 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id p8L0aa7i009290; Tue, 20 Sep 2011 20:36:37 -0400 (EDT) To: Craig Ringer cc: Royce Ausburn , pgsql-performance Subject: Re: Prepared statements and suboptimal plans In-reply-to: <4E792417.5080205@ringerc.id.au> References: <4E792417.5080205@ringerc.id.au> Comments: In-reply-to Craig Ringer message dated "Wed, 21 Sep 2011 07:39:03 +0800" Date: Tue, 20 Sep 2011 20:36:35 -0400 Message-ID: <9289.1316565395@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-2.404 tagged_above=-10 required=5 tests=BAYES_00=-1.9, RP_MATCHES_RCVD=-0.504 X-Spam-Level: X-Archive-Number: 201109/297 X-Sequence-Number: 45073 Craig Ringer writes: > On 21/09/2011 7:27 AM, Royce Ausburn wrote: >> We've been worst hit by this query on an 8.3 site. Another site is >> running 8.4. Have there been improvements in this area recently? >> Upgrading to 9.0 might be viable for us. > Tom just mentioned that 9.1 will be able to re-plan parameterized > prepared statements, so this issue will go away. 9.2, sorry, not 9.1. We could use some motivated people testing that aspect of GIT HEAD, though, since I doubt the policy for when to re-plan is quite ideal yet. regards, tom lane