Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: Christoph Berg <myon@debian.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2019-06-04T15:30:44Z
Lists: pgsql-hackers 
Andrew Gierth <andrew@tao11.riddles.org.uk> 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.

This is assuming that the tzdb data has a concept of a canonical name
for a zone, which unfortunately it does not.  UTC, UCT, Etc/UTC,
and about four other strings are equivalent names for the same zone
so far as one can tell from the installed data.

We could imagine layering some additional data on top of tzdb,
but I don't much want to go there from a maintenance standpoint.

			regards, tom lane

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.