From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: ysangkok@gmail.com, Pg Docs <pgsql-docs@lists.postgresql.org>
Subject: Re: Second-granular timezone offset format not documented
Date: Mon, 05 Jul 2021 10:04:27 -0400
Message-ID: <1438453.1625493867@sss.pgh.pa.us> (raw)
In-Reply-To: <CA+hUKGK6BNyxbaynMdp6bGgsik+x9Q0hnKvZxgFd3HkPC=ko2w@mail.gmail.com>
References: <162543102827.697.5755498651217979813@wrigleys.postgresql.org>
<CA+hUKGK6BNyxbaynMdp6bGgsik+x9Q0hnKvZxgFd3HkPC=ko2w@mail.gmail.com>
Thomas Munro <thomas.munro@gmail.com> writes:
> As for whether it's valid, that's coming from the IANA tz dataset. It
> has a moment that it believes standard time to have begun at each
> location, in this case:
> Z America/Mexico_City -6:36:36 - LMT 1922 Ja 1 0:23:24
> https://en.wikipedia.org/wiki/Time_in_Mexico#History seems to agree on
> the year at least. That "local mean time" offset is computed from the
> location's longitude, for lack of anything better. The tzinfo
> "Theory" file has a bunch of disclaimers about pre-1970 data though,
> including "the tz database's LMT offsets should not be considered
> meaningful".
I tried to interest them in dropping the LMT idea altogether [1].
Unsurprisingly, the proposal went nowhere.
regards, tom lane
[1] http://mm.icann.org/pipermail/tz/2021-May/030114.html
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-docs@postgresql.org
Cc: tgl@sss.pgh.pa.us, thomas.munro@gmail.com, pgsql-docs@lists.postgresql.org
Subject: Re: Second-granular timezone offset format not documented
In-Reply-To: <1438453.1625493867@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox