Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id 5515C1337BA8 for ; Mon, 24 Jan 2011 13:33:48 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 87643-05 for ; Mon, 24 Jan 2011 17:33:41 +0000 (UTC) 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 E6A411337B90 for ; Mon, 24 Jan 2011 13:33:40 -0400 (AST) 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 p0OHXYea009659; Mon, 24 Jan 2011 12:33:34 -0500 (EST) To: "Kevin Grittner" cc: "Robert Haas" , JPalmer@linz.govt.nz, pgsql-performance@postgresql.org, andy@squeakycode.net Subject: Re: Possible to improve query plan? In-reply-to: <4D3D59810200002500039B05@gw.wicourts.gov> References: <4D341E6802000025000396AF@gw.wicourts.gov> <4D3D59810200002500039B05@gw.wicourts.gov> Comments: In-reply-to "Kevin Grittner" message dated "Mon, 24 Jan 2011 10:50:41 -0600" Date: Mon, 24 Jan 2011 12:33:34 -0500 Message-ID: <9658.1295890414@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201101/218 X-Sequence-Number: 42005 "Kevin Grittner" writes: > Robert Haas wrote: >> But isn't 13.5 seconds awfully slow to scan 149557 rows? The sort >> is sorting 23960kB. Dividing that by 149557 rows gives ~169 >> bytes/per row > You're right. I would expect 9 ms as per tuple as a worst case if > it doesn't need to go to TOAST data. Caching, multiple rows per > page, or adjacent pages should all tend to bring it down from there. > How does it get to 90 ms per row with rows that narrow? Um, that looks like 90 usec per row, not msec. regards, tom lane