Re: IANA timezone abbreviations versus timezone_abbreviations

On 12/13/24 12:33 AM, Tom Lane wrote:
> What I think we should do about this is to teach timestamp
> input to look into the current IANA time zone to see if it
> knows the given abbreviation, and if so use that meaning
> regardless of what timezone_abbreviations might say. This
> isn't particularly hard, and it doesn't appear to cost
> anything speed-wise, but is there anybody out there who
> is relying on the current behavior?

I am not convinced this is an improvement. While this patch removes the
round-trip hazard it also makes it confusing to use the
timezone_abbreviations GUC since it can be overridden by IANA data based
on your current timezone. So you need to know all the, sometimes weird,
names for your current timezone. Seems unnecessarily hard to reason
about and wouldn't most people who use timezone_abbreviations rely on
the current behavior?

But that said I personally only use ISO timestamps with numerical
offsets. Partially to avoid all this mess.

Andreas