Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h46AB-0005hC-KU for pgsql-hackers@arkaria.postgresql.org; Wed, 13 Mar 2019 15:51:27 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1h46AA-0002DK-B3 for pgsql-hackers@arkaria.postgresql.org; Wed, 13 Mar 2019 15:51:26 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h46AA-0002DD-3g for pgsql-hackers@lists.postgresql.org; Wed, 13 Mar 2019 15:51:26 +0000 Received: from gauss.credativ.com ([93.94.130.89]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h46A7-0003CY-Nz for pgsql-hackers@lists.postgresql.org; Wed, 13 Mar 2019 15:51:25 +0000 Received: from gauss.credativ.com (localhost [127.0.0.1]) by gauss.credativ.com (Postfix) with ESMTP id E8A891E36F4; Wed, 13 Mar 2019 16:51:22 +0100 (CET) Received: from kohn.fritz.box (ppp-188-174-36-161.dynamic.mnet-online.de [188.174.36.161]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: mba@gauss.credativ.com) by gauss.credativ.com (Postfix) with ESMTPSA id 89C131E1BC7; Wed, 13 Mar 2019 16:51:22 +0100 (CET) Message-ID: <1552492283.4947.73.camel@credativ.de> Subject: Re: Offline enabling/disabling of data checksums From: Michael Banck To: Magnus Hagander , Sergei Kornilov Cc: Michael Paquier , Fabien COELHO , PostgreSQL Developers Date: Wed, 13 Mar 2019 16:51:23 +0100 In-Reply-To: References: <20181221201616.GD4974@nighthawk.caipicrew.dd-dns.de> <20190311045323.GE1818@paquier.xyz> <155231347133.16480.11453587097036807558.pgcf@coridan.postgresql.org> <1552385626.4947.50.camel@credativ.de> <20190312124403.GM13812@paquier.xyz> <20190313021621.GP13812@paquier.xyz> <20190313093150.GE2988@paquier.xyz> <20190313101021.GF2988@paquier.xyz> <5217311552474471@myt2-66bcb87429e6.qloud-c.yandex.net> <140161552477211@iva5-84bc572481fe.qloud-c.yandex.net> Organization: credativ GmbH Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk Hi, Am Mittwoch, den 13.03.2019, 12:43 +0100 schrieb Magnus Hagander: > I think this is dangerous enough that it needs to be enforced and not > documented. Changing the cluster ID might have some other side-effects, I think there are several cloud-native 3rd party solutions that use the cluster ID as some kind of unique identifier for an instance. It might not be an issue in practise, but then again, it might break other stuff down the road. Another possibility would be to extend the replication protocol's IDENTIFY_SYSTEM command to also report the checksum version so that the standby can check against the local control file on startup. But I am not sure we can easily extend IDENTIFY_SYSTEM this way nor whether we should for this rather corner-casey thing? Michael -- Michael Banck Projektleiter / Senior Berater Tel.: +49 2166 9901-171 Fax: +49 2166 9901-100 Email: michael.banck@credativ.de credativ GmbH, HRB Mönchengladbach 12080 USt-ID-Nummer: DE204566209 Trompeterallee 108, 41189 Mönchengladbach Geschäftsführung: Dr. Michael Meskes, Jörg Folz, Sascha Heuer Unser Umgang mit personenbezogenen Daten unterliegt folgenden Bestimmungen: https://www.credativ.de/datenschutz