Received: from localhost (unknown [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 4BA6464FC52 for ; Mon, 24 Nov 2008 11:55:22 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 46848-07 for ; Mon, 24 Nov 2008 11:55:15 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.186]) by mail.postgresql.org (Postfix) with ESMTP id CEE3A64FC40 for ; Mon, 24 Nov 2008 11:55:14 -0400 (AST) Received: by nf-out-0910.google.com with SMTP id c7so1135335nfi.23 for ; Mon, 24 Nov 2008 07:55:12 -0800 (PST) Received: by 10.210.58.13 with SMTP id g13mr3703553eba.192.1227542111983; Mon, 24 Nov 2008 07:55:11 -0800 (PST) Received: from ?80.222.79.63? (dsl-hkibrasgw2-fe4fde00-63.dhcp.inet.fi [80.222.79.63]) by mx.google.com with ESMTPS id k9sm47002nfh.23.2008.11.24.07.55.09 (version=TLSv1/SSLv3 cipher=RC4-MD5); Mon, 24 Nov 2008 07:55:10 -0800 (PST) Message-ID: <492ACE5C.70905@enterprisedb.com> Date: Mon, 24 Nov 2008 17:55:08 +0200 Organization: EnterpriseDB User-Agent: Mozilla-Thunderbird 2.0.0.17 (X11/20081018) MIME-Version: 1.0 To: Gregory Stark CC: Tom Lane , PostgreSQL-development Subject: Re: Visibility map, partial vacuums References: <4905AE17.7090305@enterprisedb.com> <491D376B.9000608@enterprisedb.com> <491D7F52.6070908@enterprisedb.com> <4925664C.3090605@enterprisedb.com> <26361.1227467112@sss.pgh.pa.us> <492A6032.6080000@enterprisedb.com> <18086.1227537479@sss.pgh.pa.us> <87ljv9rvv0.fsf@oxford.xeocode.com> In-Reply-To: <87ljv9rvv0.fsf@oxford.xeocode.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit From: Heikki Linnakangas X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=0 tagged_above=0 required=5 tests=none X-Spam-Level: X-Archive-Number: 200811/1583 X-Sequence-Number: 128295 Gregory Stark wrote: > However I'm a bit puzzled how you could possibly maintain this frozenxid. As > soon as you freeze an xid you'll have to visit all the other pages covered by > that visibility map page to see what the new value should be. Right, you could only advance it when you scan all the pages covered by the visibility map page. But that's better than having to scan the whole relation. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com