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 872389DC99D for ; Wed, 22 Feb 2006 13:13:07 -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 47323-04 for ; Wed, 22 Feb 2006 13:13:05 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from mail.Mi8.com (d01gw01.mi8.com [63.240.6.47]) by postgresql.org (Postfix) with ESMTP id BF6579DC9AD for ; Wed, 22 Feb 2006 13:13:04 -0400 (AST) Received: from 172.16.1.25 by mail.Mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D1)); Wed, 22 Feb 2006 12:12:36 -0500 X-Server-Uuid: 241911D6-425B-44B9-A073-E3FE0F8FC774 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.175]) by D01HOST03.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Wed, 22 Feb 2006 12:12:03 -0500 Received: from 67.103.45.218 ([67.103.45.218]) by MI8NYCMAIL06.Mi8.com ( [172.16.1.219]) via Exchange Front-End Server mi8owa.mi8.com ( [172.16.1.105]) with Microsoft Exchange Server HTTP-DAV ; Wed, 22 Feb 2006 17:12:02 +0000 User-Agent: Microsoft-Entourage/11.2.1.051004 Date: Wed, 22 Feb 2006 09:11:50 -0800 Subject: Re: Good News re count(*) in 8.1 From: "Luke Lonergan" To: "Kevin Grittner" , pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] Good News re count(*) in 8.1 Thread-Index: AcY30SXcnUYXYsFBQPGESRUQSJ7U+gAAevHz In-Reply-To: <43FC4384.EE98.0025.0@wicourts.gov> MIME-Version: 1.0 X-OriginalArrivalTime: 22 Feb 2006 17:12:03.0285 (UTC) FILETIME=[198BB050:01C637D3] X-WSS-ID: 6FE2440A31W10045603-07-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=1.324 required=5 tests=[AWL=0.071, RCVD_NUMERIC_HELO=1.253] X-Spam-Score: 1.324 X-Spam-Level: * X-Archive-Number: 200602/345 X-Sequence-Number: 17331 Kevin, On 2/22/06 8:57 AM, "Kevin Grittner" wrote: > I hesitate to raise this issue again, but I've noticed something which I > thought might be worth mentioning. I've never thought the performance > of count(*) on a table was a significant issue, but I'm prepared to say > that -- for me, at least -- it is officially and totally a NON-issue. Cool! Kudos to Tom for implementing the improvements in the executor to move tuples faster through the pipeline. We see a CPU limit (yes, another limit) of about 300MB/s now on Opteron 250 processors running on Linux. The filesystem can do 420MB/s sequential scan in 8k pages, but Postgres count(*) on 8.1.3 can only do about 300MB/s. This is still a very large improvement over past versions, but we'd always like to see more... - Luke