Horton

Re: UCT (Re: pgsql: Update time zone data files to tzdata release 2019a.)

Andrew Gierth <andrew@tao11.riddles.org.uk>

View thread View on postgr.es
From: Andrew Gierth <andrew@tao11.riddles.org.uk>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Christoph Berg <myon@debian.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2019-06-14T18:24:50Z
Lists: pgsql-hackers 
>>>>> "Tom" == Tom Lane <tgl@sss.pgh.pa.us> writes:

 >>> Anyway, moving on to the question of what should we do about this,
 >>> I don't really have anything better to offer than back-patching
 >>> 23bd3cec6.

 >> The PG12 behavior seems sane, so +1.

 Tom> OK, I'll make that happen.

This isn't good enough, because it still picks "UCT" on a system with no
/etc/localtime and no TZ variable. Testing on HEAD as of 3da73d683 (on
FreeBSD, but it'll be the same anywhere else):

% ls -l /etc/*time*
ls: /etc/*time*: No such file or directory

% env -u TZ bin/initdb -D data -E UTF8 --no-locale
[...]
selecting default timezone ... UCT

We need to absolutely prefer UTC over UCT if both match.

-- 
Andrew (irc:RhodiumToad)

Commits

  1. Tweak our special-case logic for the IANA "Factory" timezone.

  2. Avoid choosing "localtime" or "posixrules" as TimeZone during initdb.

  3. Prefer timezone name "UTC" over alternative spellings.

  4. Attempt to identify system timezone by reading /etc/localtime symlink.

  5. Update time zone data files to tzdata release 2019a.