Received: from localhost (unknown [200.46.208.211]) by mail.postgresql.org (Postfix) with ESMTP id 8EB0B63321F for ; Mon, 9 Mar 2009 13:31:39 -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 40869-03 for ; Mon, 9 Mar 2009 13:31:36 -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 CE76E632A91 for ; Mon, 9 Mar 2009 13:31:37 -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 n29GVYg1027650; Mon, 9 Mar 2009 12:31:34 -0400 (EDT) To: Mario Splivalo cc: pgsql-performance@postgresql.org Subject: Re: Query much slower when run from postgres function In-reply-to: <49B51B60.6030600@megafon.hr> References: <49B51B60.6030600@megafon.hr> Comments: In-reply-to Mario Splivalo message dated "Mon, 09 Mar 2009 14:36:32 +0100" Date: Mon, 09 Mar 2009 12:31:34 -0400 Message-ID: <27649.1236616294@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: 200903/62 X-Sequence-Number: 32984 Mario Splivalo writes: > Now I'm confused, why is 'sql' function much slower than 'direct' SELECT? Usually the reason for this is that the planner chooses a different plan when it has knowledge of the particular value you are searching for than when it does not. I suppose 'service_id' has a very skewed distribution and you are looking for an uncommon value? regards, tom lane