Re: BUG #1993: Adding/subtracting negative time intervals

John R Pierce <pierce@hogranch.com> writes:
> the whole DST thing falls apart when you deal with places that don't
> respect it...  arizona (except the navajo nation), for instance....

> it would be impossible to calculate the 'correct' answer without knowing
> the exact location...

No, rather say "without knowing the correct timezone".  All of this is
about doing the calculations properly according to the rules of the
current TimeZone setting.  It's irrelevant whether the calculations are
correct with respect to some other timezone rules; obviously they won't
be.

(A separate issue is whether we know the rules for any particular
timezone you might wish to use.  I'm pretty sure the zic database covers
everything anyone could possibly care about, though ;-))

            regards, tom lane