X-Original-To: pgsql-performance-postgresql.org@postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id B58979FA111 for ; Tue, 12 Sep 2006 19:19:04 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.208.251]) (amavisd-new, port 10024) with ESMTP id 87382-05 for ; Tue, 12 Sep 2006 19:19:00 -0300 (ADT) 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 D453D9FA0B9 for ; Tue, 12 Sep 2006 19:18:59 -0300 (ADT) Received: from 172.16.1.148 by mail.Mi8.com with ESMTP (- Welcome to Mi8 Corporation www.Mi8.com (D1)); Tue, 12 Sep 2006 18:18:46 -0400 X-Server-Uuid: 241911D6-425B-44B9-A073-E3FE0F8FC774 Received: from MI8NYCMAIL06.Mi8.com ([172.16.1.160]) by D01HOST02.Mi8.com with Microsoft SMTPSVC(6.0.3790.1830); Tue, 12 Sep 2006 18:18:13 -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 ( [172.16.1.118]) with Microsoft Exchange Server HTTP-DAV ; Tue, 12 Sep 2006 22:18:13 +0000 User-Agent: Microsoft-Entourage/11.2.5.060620 Date: Tue, 12 Sep 2006 15:18:11 -0700 Subject: Re: Poor performance on seq scan From: "Luke Lonergan" To: "Laszlo Nagy" , pgsql-performance@postgresql.org Message-ID: Thread-Topic: [PERFORM] Poor performance on seq scan Thread-Index: AcbWuVUAk6EaFEKsEduoJAAWy4o9DA== In-Reply-To: <45072B61.3080506@designaproduct.biz> MIME-Version: 1.0 X-OriginalArrivalTime: 12 Sep 2006 22:18:13.0720 (UTC) FILETIME=[569F1D80:01C6D6B9] X-WSS-ID: 6919EDCC32S3592849-03-01 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=2.652 tagged_above=0 required=5 tests=AWL, BIZ_TLD, RCVD_NUMERIC_HELO X-Spam-Level: ** X-Archive-Number: 200609/106 X-Sequence-Number: 20792 Lazlo, On 9/12/06 2:49 PM, "Laszlo Nagy" wrote: > I'm using FreeBSD, and not just because it dynamically alters the > priority of long running processes. :-) Understood. Linux and FreeBSD often share some driver technology. I have had extremely bad performance historically with onboard SATA chipsets on Linux. The one exception has been with the Intel based chipsets (not the CPU, the I/O chipset). It is very likely that you are having problems with the driver for the chipset. Are you running RAID1 in hardware? If so, turn it off and see what the performance is. The onboard hardware RAID is worse than useless, it actually slows the I/O down. If you want RAID with onboard chipsets, use software RAID, or buy an adapter from 3Ware or Areca for $200. - Luke