Horton

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

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Christoph Berg <myon@debian.org>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2019-06-04T15:53:30Z
Lists: pgsql-hackers 
Hi,

On 2019-06-04 11:27:31 -0400, Tom Lane wrote:
> Hm, I don't have a Debian machine at hand, but I'm unable to
> reproduce this using macOS or RHEL.  I tried things like
> 
> $ TZ=UTC initdb
> ...
> selecting default timezone ... UTC
> ...

On debian unstable that's what I get too, both with system and PG
tzdata.


> BTW, does Debian set up /etc/timezone as a symlink, by any chance,
> rather than a copy or hard link?  If it's a symlink, we could improve
> matters by teaching identify_system_timezone() to inspect it.

On my system it's a copy (link count 1, not a symlink). Or did you mean
/etc/localtime? Because that's indeed a symlink.

If I set the system-wide default, using dpkg-reconfigure -plow tzdata,
to UTC I *do* get Etc/UTC.

root@alap4:/home/andres/src/postgresql# cat /etc/timezone
Etc/UTC
root@alap4:/home/andres/src/postgresql# ls -l /etc/timezone
-rw-r--r-- 1 root root 8 Jun  4 15:44 /etc/timezone

selecting default timezone ... Etc/UTC

This is independent of being built with system or non-system tzdata.

Enabling debugging shows:

selecting default timezone ... symbolic link "/etc/localtime" contains "/usr/share/zoneinfo/Etc/UCT"
TZ "Etc/UCT" gets max score 5200
Etc/UCT

Greetings,

Andres Freund

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.