Received: from localhost (maia-4.hub.org [200.46.204.183]) by postgresql.org (Postfix) with ESMTP id BBDAF9FB798 for ; Wed, 16 May 2007 17:30:29 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 48716-08 for ; Wed, 16 May 2007 17:30:25 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 9BEB09FBB13 for ; Wed, 16 May 2007 17:30:25 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.1/8.14.1) with ESMTP id l4GKUIiS007146; Wed, 16 May 2007 16:30:18 -0400 (EDT) To: Heikki Linnakangas cc: Alvaro Herrera , Chris Browne , pgsql-patches@postgresql.org Subject: Re: [DOCS] Autovacuum and XID wraparound In-reply-to: <464B60A7.3070106@enterprisedb.com> References: <20070514011740.GH14860@fetter.org> <23394.1179108400@sss.pgh.pa.us> <1179117269.6047.3.camel@goldbach> <60sl9z6tln.fsf@dba2.int.libertyrms.com> <20070514221619.GC8916@alvh.no-ip.org> <857.1179184222@sss.pgh.pa.us> <20070515221347.GT12731@alvh.no-ip.org> <23362.1179292856@sss.pgh.pa.us> <20070516124420.GA4582@alvh.no-ip.org> <464B0E5A.1070807@enterprisedb.com> <6549.1179344646@sss.pgh.pa.us> <464B60A7.3070106@enterprisedb.com> Comments: In-reply-to Heikki Linnakangas message dated "Wed, 16 May 2007 20:51:03 +0100" Date: Wed, 16 May 2007 16:30:18 -0400 Message-ID: <7145.1179347418@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200705/253 X-Sequence-Number: 2353 Heikki Linnakangas writes: > Tom Lane wrote: >> Heikki Linnakangas writes: >>> Now that I think this a bit more, I think CLUSTER should freeze the >>> tuples. >> >> I disagree with that... > Ok. Why? It's removing potentially-important data without any notice or recourse to the user. There seems to be a contingent around here that thinks that as soon as xmin is older than GlobalXmin it is no longer of interest to anyone, but I have lost count of how often I have found it invaluable for forensic purposes. I have resisted having VACUUM freeze tuples before they've reached a quite-respectable age, and I object to having CLUSTER do it either. I could maybe accept a CLUSTER FREEZE option to do this, but that's not what's in the patch. regards, tom lane