[tz] Irish Standard Time vs Irish Summer Time

Tom Lane tgl at sss.pgh.pa.us
Fri Jan 19 00:39:50 UTC 2018

Zefram <zefram at fysh.org> writes:
> There was indeed a significant chance of the negative SAVE value breaking
> alternate zic implementations, and now that that's turned out to be
> the case that's good cause to postpone this correction, or at least the
> expressing of it in this natural manner.  The tzdb does have unusually
> high stability requirements.  But that's not a reason to keep the database
> forever inaccurate.

I'm not sure that it's "inaccurate".  The question is more about what is
the meaning of tm_isdst = 1.  It's clear from this discussion that an
awful lot of code believes it means "local time is advanced now compared
to what it is when tm_isdst = 0".  Arguing that it should reflect a
legalistic definition of DST, rather than an operational definition,
is just an argument; it's not conclusive.

FWIW, I share the opinion that this change was misguided.

			regards, tom lane

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