X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id 5495E9DCABC for ; Thu, 12 Jan 2006 00:33:28 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 79692-05 for ; Thu, 12 Jan 2006 00:33:26 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 0209E9DCA65 for ; Thu, 12 Jan 2006 00:33:25 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id k0C4XNxn000936; Wed, 11 Jan 2006 23:33:23 -0500 (EST) To: Mark Liberman cc: pgsql-performance@postgresql.org Subject: Re: Stable function being evaluated more than once in a single query In-reply-to: <200601111641.20627.mliberman@mixedsignals.com> References: <200601111641.20627.mliberman@mixedsignals.com> Comments: In-reply-to Mark Liberman message dated "Wed, 11 Jan 2006 16:41:20 -0800" Date: Wed, 11 Jan 2006 23:33:23 -0500 Message-ID: <935.1137040403@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.085 required=5 tests=[AWL=0.085] X-Spam-Score: 0.085 X-Spam-Level: X-Archive-Number: 200601/148 X-Sequence-Number: 16626 Mark Liberman writes: > I've got a set-returning function, defined as STABLE, that I reference twice > within a single query, yet appears to be evaluated via two seperate function > scans. There is no guarantee, express or implied, that this won't be the case. (Seems like we just discussed this a couple days ago...) regards, tom lane