Received: from localhost (maia-2.hub.org [200.46.204.187]) by postgresql.org (Postfix) with ESMTP id 944EF9FB3B2 for ; Thu, 26 Jul 2007 19:43:44 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.187]) (amavisd-maia, port 10024) with ESMTP id 90809-05 for ; Thu, 26 Jul 2007 19:43:31 -0300 (ADT) X-Greylist: delayed 00:06:39.311263 by SQLgrey-1.7.5 Received: from smtp121.sbc.mail.sp1.yahoo.com (smtp121.sbc.mail.sp1.yahoo.com [69.147.64.94]) by postgresql.org (Postfix) with SMTP id CF8369FB30C for ; Thu, 26 Jul 2007 19:43:39 -0300 (ADT) Received: (qmail 99553 invoked from network); 26 Jul 2007 22:36:58 -0000 Received: from unknown (HELO ?10.1.1.100?) (scottmf76@68.127.170.153 with plain) by smtp121.sbc.mail.sp1.yahoo.com with SMTP; 26 Jul 2007 22:36:58 -0000 X-YMail-OSG: WDzdHDwVM1mbw.IfWROHKpmHKiI_oKKCBH4r_eGmDhUzYE2e6jUI79641ckXR7bYZLt5UpZYPw-- Mime-Version: 1.0 (Apple Message framework v752.3) Content-Transfer-Encoding: 7bit Message-Id: Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed To: pgsql-performance@postgresql.org From: Scott Feldstein Subject: update, truncate and vacuum Date: Thu, 26 Jul 2007 15:36:50 -0700 X-Mailer: Apple Mail (2.752.3) X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200707/376 X-Sequence-Number: 26060 Hi, I have a couple questions about how update, truncate and vacuum would work together. 1) If I update a table foo (id int, value numeric (20, 6)) with update foo set value = 100 where id = 1 Would a vacuum be necessary after this type of operation since the updated value is a numeric? (as opposed to a sql type where its size could potentially change i.e varchar) 2) After several updates/deletes to a table, if I truncate it, would it be necessary to run vacuum in order to reclaim the space? thanks, Scott