Received: from maia.hub.org (maia-5.hub.org [200.46.204.29]) by mail.postgresql.org (Postfix) with ESMTP id C5E47632BCA for ; Mon, 30 Aug 2010 22:59:01 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.29]) (amavisd-maia, port 10024) with ESMTP id 98067-04 for ; Tue, 31 Aug 2010 01:58:54 +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 B8429632B6C for ; Mon, 30 Aug 2010 22:58:53 -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 o7V1wk2q021904; Mon, 30 Aug 2010 21:58:46 -0400 (EDT) To: Scott Carey cc: Yeb Havinga , Greg Smith , Eliot Gable , "pgsql-performance@postgresql.org" Subject: Re: GPU Accelerated Sorting In-reply-to: References: <4C7BBAA1.6040808@2ndquadrant.com> <4C7C05B2.7030207@gmail.com> Comments: In-reply-to Scott Carey message dated "Mon, 30 Aug 2010 18:17:48 -0700" Date: Mon, 30 Aug 2010 21:58:45 -0400 Message-ID: <21903.1283219925@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: 201008/349 X-Sequence-Number: 40192 Scott Carey writes: > On a similar note, is Postgres' Quicksort a dual-pivot quicksort? This can be up to 2x as fast as a normal quicksort (25% fewer swap operations, and swap operations are more expensive than compares for most sorts). In Postgres, the swaps are pretty much free compared to the comparisons. Sorry, but the above doesn't especially tempt me... regards, tom lane