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

Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2019-06-06 12:51:30 -0400, Tom Lane wrote:
>> Sure, that is intentionally a behavior change in this situation.
>> The theory is that if "Etc/UCT" is what the user put in /etc/localtime,
>> then that's the spelling she wants. See 23bd3cec6.

> Right, I'm not complaining about that. I'm just noting that that
> explains the cross-version divergence.

It explains some cross-version divergence for sure. What I'm still not
clear about is whether Christoph's report is entirely that, or whether
there's some additional factor we don't understand yet.

> As you can see the switch from Etc/UTC to UCT does happen here
> (presumably in any branch before 12). Which did not happen before the
> import of 2019a / when using a system tzdata that's before
> that.

Right. Before 2019a, UCT would not have been a match to a system
setting of UTC because the zone abbreviation reported by localtime()
was different. Now it's the same abbreviation.

Maybe we should consider back-patching 23bd3cec6.

regards, tom lane