Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id DB93C633226 for ; Tue, 10 Mar 2009 14:20:57 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.208.211]) (amavisd-maia, port 10024) with ESMTP id 03220-03 for ; Tue, 10 Mar 2009 14:20:55 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id 9C38C62FEFB for ; Tue, 10 Mar 2009 14:20:49 -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 n2AHKlsL000356; Tue, 10 Mar 2009 13:20:47 -0400 (EDT) To: fche@redhat.com (Frank Ch. Eigler) cc: Mario Splivalo , pgsql-performance@postgresql.org Subject: Re: Query much slower when run from postgres function In-reply-to: References: <49B51B60.6030600@megafon.hr> <27649.1236616294@sss.pgh.pa.us> Comments: In-reply-to fche@redhat.com (Frank Ch. Eigler) message dated "Tue, 10 Mar 2009 10:40:51 -0400" Date: Tue, 10 Mar 2009 13:20:47 -0400 Message-ID: <355.1236705647@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200903/81 X-Sequence-Number: 33003 fche@redhat.com (Frank Ch. Eigler) writes: > For a prepared statement, could the planner produce *several* plans, > if it guesses great sensitivity to the parameter values? Then it > could choose amongst them at run time. We've discussed that in the past. "Choose at runtime" is a bit more easily said than done though --- you can't readily flip between plan choices part way through, if you've already emitted some result rows. regards, tom lane