X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (mx1.hub.org [200.46.208.251]) by postgresql.org (Postfix) with ESMTP id 9612D9FADD1 for ; Tue, 30 May 2006 17:24:41 -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 10935-04 for ; Tue, 30 May 2006 17:24:37 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey- Received: from peufeu.com (boutiquenumerique.com [82.67.9.10]) by postgresql.org (Postfix) with ESMTP id CFD609FA5E9 for ; Tue, 30 May 2006 17:24:36 -0300 (ADT) Received: (qmail 15318 invoked from network); 30 May 2006 22:24:34 +0200 Received: from boutiquenumerique.com (HELO apollo13) (82.67.9.10) by boutiquenumerique.com with SMTP; 30 May 2006 22:24:34 +0200 To: "Jonathan Blitz" , "'Francisco Reyes'" Cc: pgsql-performance@postgresql.org Subject: Re: Adding and filling new column on big table References: <012501c6842c$bb8438f0$ddf71005@jonathanlaptop> Message-ID: Date: Tue, 30 May 2006 22:24:32 +0200 From: PFC Content-Type: text/plain; format=flowed; delsp=yes; charset=utf-8 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In-Reply-To: <012501c6842c$bb8438f0$ddf71005@jonathanlaptop> User-Agent: Opera M2/8.54 (Linux, build 1745) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200605/536 X-Sequence-Number: 19323 >> Most laptop drives are only 5,400 RPM which would make a transaction >> like >> you are describing likely take a while. > > Not sure what my one is but it is new(ish). If you're doing data intensive operations (like a big update which looks like what you're doing) it will write many megabytes to the harddrive... my laptop HDD (5400 rpm) does about 15 MB/s throughput while a standard desktop 7200rpm drive does 55-60 MB/s throughput. Plus, seek times on a laptop drive are horrendous.