Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bciJe-0005ZC-22 for pgsql-admin@arkaria.postgresql.org; Thu, 25 Aug 2016 00:14:42 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1bciJd-0001yd-7m for pgsql-admin@arkaria.postgresql.org; Thu, 25 Aug 2016 00:14:41 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1bciJc-0001yL-GI for pgsql-admin@postgresql.org; Thu, 25 Aug 2016 00:14:40 +0000 Received: from mailout.easymail.ca ([64.68.201.169]) by makus.postgresql.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.84_2) (envelope-from ) id 1bciJV-0004zp-AT for pgsql-admin@postgresql.org; Thu, 25 Aug 2016 00:14:39 +0000 Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id 19908EB03; Wed, 24 Aug 2016 20:14:32 -0400 (EDT) X-Virus-Scanned: Debian amavisd-new at mailout.easymail.ca X-Spam-Flag: NO X-Spam-Score: -3.784 X-Spam-Level: X-Spam-Status: No, score=-3.784 required=5 tests=[ALL_TRUSTED=-1.8, AWL=-0.077, BAYES_00=-2.599, DNS_FROM_AHBL_RHSBL=0.692] Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (easymail-mailout.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Abm2zcZ4Xkl8; Wed, 24 Aug 2016 20:14:31 -0400 (EDT) Received: from [192.168.2.118] (unknown [8.39.228.5]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout.easymail.ca (Postfix) with ESMTPSA id 3F638E708; Wed, 24 Aug 2016 20:14:31 -0400 (EDT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2104\)) Subject: Re: Does CLUSTER generate WAL data? From: Scott Ribe In-Reply-To: Date: Wed, 24 Aug 2016 18:14:29 -0600 Cc: "David G. Johnston" , "pgsql-admin@postgresql.org" Content-Transfer-Encoding: quoted-printable Message-Id: References: To: Craig James X-Mailer: Apple Mail (2.2104) X-Pg-Spam-Score: -2.6 (--) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-admin Precedence: bulk Sender: pgsql-admin-owner@postgresql.org On Aug 24, 2016, at 6:09 PM, Craig James wrote: >=20 > Right, I understand that the WAL has to record the operation. But I'm not= sure that answers the question. If the contents of the WAL are, "copy this= table to that table in index order", then no data from the table itself wi= ll be in the WAL. On the other hand, if the contents of the WAL are "create= a new table, and then insert all of this data", then the WAL records will = be huge. >=20 > Which is it? WAL records changes at the page level, not commands; so it will be the one = you don't want. --=20 Scott Ribe scott_ribe@elevated-dev.com http://www.elevated-dev.com/ https://www.linkedin.com/in/scottribe/ (303) 722-0567 voice --=20 Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin