Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id BDD28B5DBBF for ; Thu, 16 Jun 2011 15:21:50 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 37406-01 for ; Thu, 16 Jun 2011 18:21:44 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by mail.postgresql.org (Postfix) with ESMTP id DE8A2B5DC2D for ; Thu, 16 Jun 2011 15:21:41 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id p5GILetq006560; Thu, 16 Jun 2011 14:21:40 -0400 (EDT) To: Andreas Berger <4postgres@gmail.com> cc: pgsql-admin@postgresql.org Subject: Re: alter table without an ACCESS EXCLUSIVE lock In-reply-to: References: Comments: In-reply-to Andreas Berger <4postgres@gmail.com> message dated "Thu, 16 Jun 2011 16:55:04 +0200" Date: Thu, 16 Jun 2011 14:21:40 -0400 Message-ID: <6559.1308248500@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.91 tagged_above=-10 required=5 tests=BAYES_00=-1.9, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201106/99 X-Sequence-Number: 37725 Andreas Berger <4postgres@gmail.com> writes: > i'm searching for a solution for changing the type of a column, e.g. from > varchar(128) to varchar(512), without an ACCESS EXCLUSIVE lock. That specific case (increasing the max length of a varchar column) could be handled by hacking the pg_attribute.atttypmod entry for the column, since no change in the actual data is required. However, I have no idea whether your replication environment would cope with such a change --- experimenting on a non-production setup would be highly recommendable. regards, tom lane