Re: postgres_fdw fails because GMT != UTC

On Thu, 2024-04-04 at 02:19 -0400, Tom Lane wrote:
> > ERROR:  invalid value for parameter "TimeZone": "UTC"
>
> I am not quite clear on how broken an installation needs to be to
> reject "UTC" as a time zone setting, except that the breakage cannot
> be subtle.  However, I notice that our code in pgtz.c and other
> places treats "GMT" as a hard-wired special case ... but not "UTC".
> I wonder if we ought to modify those places to force "UTC" down the
> same hard-wired paths.  If we acted like that, this would have worked
> no matter how misconfigured the installation was.
>
> An alternative answer could be to change postgres_fdw to send "GMT"
> not "UTC".  That's ugly from a standards-compliance viewpoint, but
> it would fix this problem even with a non-updated remote server,
> and I think postgres_fdw is generally intended to work with even
> very old remote servers.
>
> Or we could do both.

I think the first is desirable for reasons of general sanity, and the
second for best compatibility with old versions.

So I vote for "both".

Yours,
Laurenz Albe