Horton

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

Shay Rojansky <roji@roji.org>

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From: Shay Rojansky <roji@roji.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Thomas Munro <thomas.munro@gmail.com>, Andrew Gierth <andrew@tao11.riddles.org.uk>, Robert Haas <robertmhaas@gmail.com>, Stephen Frost <sfrost@snowman.net>, Andres Freund <andres@anarazel.de>, Christoph Berg <myon@debian.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2019-08-01T09:09:54Z
Lists: pgsql-hackers 
> I'm not sure we're any closer to a meeting of the minds on whether
> consulting zone[1970].tab is a good thing to do, but we got an actual
> user complaint[1] about how "localtime" should not be a preferred
> spelling.  So I want to go ahead and insert the discussed anti-preference
> against "localtime" and "posixrules", as per 0001 below.  If we do do
> something with zone[1970].tab, we'd still need these special rules,
> so I don't think this is blocking anything.

Just want to stress this point from a PostgreSQL driver maintainer
perspective (see here[1] for the full details). Having "localtime" as the
PostgreSQL timezone basically means that the timezone is completely opaque
from a client point of view - there is no way for clients to know what
actual timezone the server is in, and react to that. This is a limiting
factor in client development, I hope a consensus on this specific point can
be reached.

[1]
https://www.postgresql.org/message-id/CADT4RqCCnj6FKLisvT8tTPfTP4azPhhDFJqDF1JfBbOH5w4oyQ@mail.gmail.com

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.