X-Original-To: pgsql-hackers-postgresql.org@postgresql.org Received: from localhost (wm.hub.org [200.46.204.128]) by postgresql.org (Postfix) with ESMTP id 350C29FA508 for ; Sun, 23 Jul 2006 21:35:59 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.128]) (amavisd-new, port 10024) with ESMTP id 17876-08 for ; Mon, 24 Jul 2006 00:35:51 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.mi8.com (d01gw02.mi8.com [63.240.6.46]) by postgresql.org (Postfix) with ESMTP id 3ED269FA48B for ; Sun, 23 Jul 2006 21:35:51 -0300 (ADT) Received: from 172.16.1.25 by mail.mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D2)); Sun, 23 Jul 2006 20:35:40 -0400 X-Server-Uuid: 7829E76E-BB9E-4995-8473-3C0929DF7DD1 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.160]) by D01HOST03.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Sun, 23 Jul 2006 20:35:40 -0400 Received: from 63.80.24.130 ([63.80.24.130]) by MI8NYCMAIL06.Mi8.com ( [172.16.1.219]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.108]) with Microsoft Exchange Server HTTP-DAV ; Mon, 24 Jul 2006 00:35:39 +0000 User-Agent: Microsoft-Entourage/11.2.5.060620 Date: Sun, 23 Jul 2006 17:35:37 -0700 Subject: Re: On-disk bitmap index patch From: "Luke Lonergan" To: "Tom Lane" , "Gavin Sherry" , "Jie Zhang" , "Ayush Parashar" cc: pgsql-hackers@postgresql.org Message-ID: Thread-Topic: [HACKERS] On-disk bitmap index patch Thread-Index: AcauuRTuU8BzKhqsEduOgQAWy4o9DA== In-Reply-To: <28750.1153700718@sss.pgh.pa.us> MIME-Version: 1.0 X-OriginalArrivalTime: 24 Jul 2006 00:35:40.0454 (UTC) FILETIME=[16FD9C60:01C6AEB9] X-WSS-ID: 68DACA5648W8886078-01-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=1.5 tagged_above=0 required=5 tests=RCVD_NUMERIC_HELO X-Spam-Level: * X-Archive-Number: 200607/1002 X-Sequence-Number: 86857 Tom, On 7/23/06 5:25 PM, "Tom Lane" wrote: > If the column is sufficiently low cardinality, you might as well just do > a seqscan --- you'll be hitting most of the heap's pages anyway. I'm > still waiting to be convinced that there's a sweet spot wide enough to > justify supporting another index AM. (I'm also wondering whether this > doesn't overlap the use-case for GIN.) We presented them at the Postgres Anniversary summit talk (Bruce M. was there) and the reaction was let's get this into 8.2 because many people there (more than 5) really wanted to use it as a standard feature. A version of the slides with only the bitmap index results are located here: http://intranet.greenplum.com/bitmap-index-perf-ayush.ppt. - Luke