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 1hYBoF-0007A4-OK for pgsql-hackers@arkaria.postgresql.org; Tue, 04 Jun 2019 15:57:11 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1hYBoE-000582-KT for pgsql-hackers@arkaria.postgresql.org; Tue, 04 Jun 2019 15:57:10 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hYBoE-00050t-6W for pgsql-hackers@lists.postgresql.org; Tue, 04 Jun 2019 15:57:10 +0000 Received: from lungold.riddles.org.uk ([82.68.208.19]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1hYBoB-0003eB-7r for pgsql-hackers@postgresql.org; Tue, 04 Jun 2019 15:57:09 +0000 Received: from [192.168.127.1] (port=45615 helo=caithnard.riddles.org.uk) by lungold.riddles.org.uk with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.88 (FreeBSD)) (envelope-from ) id 1hYBo8-0005LM-EF; Tue, 04 Jun 2019 15:57:04 +0000 Received: from [127.0.0.1] (port=50171 helo=caithnard.riddles.org.uk) by caithnard.riddles.org.uk with esmtp (Exim 4.89 (FreeBSD)) (envelope-from ) id 1hYBo7-000229-O1; Tue, 04 Jun 2019 15:57:03 +0000 From: Andrew Gierth To: Tom Lane Cc: Christoph Berg , PostgreSQL Hackers Subject: Re: UCT (Re: pgsql: Update time zone data files to tzdata release 2019a.) In-Reply-To: <65811.1559662244@sss.pgh.pa.us> (Tom Lane's message of "Tue, 04 Jun 2019 11:30:44 -0400") Message-ID: <87k1e18i3q.fsf@news-spur.riddles.org.uk> References: <20190604085735.GD24018@msg.df7cb.de> <87blzdacpp.fsf@news-spur.riddles.org.uk> <65811.1559662244@sss.pgh.pa.us> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (berkeley-unix) Date: Tue, 04 Jun 2019 16:57:03 +0100 MIME-Version: 1.0 Content-Type: text/plain List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk >>>>> "Tom" == Tom Lane writes: > Andrew Gierth writes: >> I believe I pointed out a long, long time ago that this tie-breaking >> strategy was insane, and that the rule should be to prefer canonical >> names and use something else only in the case of a strictly better >> match. Tom> This is assuming that the tzdb data has a concept of a canonical Tom> name for a zone, which unfortunately it does not. UTC, UCT, Tom> Etc/UTC, and about four other strings are equivalent names for the Tom> same zone so far as one can tell from the installed data. The simplest definition is that the names listed in zone.tab or zone1970.tab if you prefer that one are canonical, and Etc/UTC and the Etc/GMT[offset] names could be regarded as canonical too. Everything else is either an alias or a backward-compatibility hack. -- Andrew (irc:RhodiumToad)