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Bruno Wolff III wrote:
Days *are* of constant length - check your nearest dictionary, which
will define it as 24 hours or the period of rotation of the earth. If
people see 'day', they think '24 hours' because that is the definition
they have been using since preschool. This breeds sleeping bugs that
nobody notices until the DST transition kicks in and events happen an
hour late or not at all.

What you are talking about is useful, but should be called calendar_day
or something that makes it obvious that it isn't using the traditional
definition.

People are used to months being ambiguous so it is less likely to cause
upsets, although it still bites people because their toolkits definition
of 'month' does not match their business rules of 'month' (which might
be 30 days, 31 days, 4 weeks, calendar month rounded down).

- --
Stuart Bishop <stuart (AT) stuartbishop (DOT) net>
http://www.stuartbishop.net/
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On Nov 5, 2004, at 5:38 PM, Stuart Bishop wrote:

Could you expand on this a bit? I'm not quite sure what you're getting
at. I think most people would say the period from noon one day until
noon the next would be 1 day. If that day spans a DST change, it will
definitely not be 24 hours, and people might agree if they're asked "is
the period from noon til noon over DST 24 hours?". They'd most likely
say no, I think. Yet, if they're asked if the same period is one day, I
think they'd answer yes. I think this is what Bruno is getting at.

Regards,

Michael Glaesemann
grzm myrealbox com


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Stuart Bishop <stuart (AT) stuartbishop (DOT) net> writes:
This is about as relevant to our problems as claiming that we should
ignore leap years because years are really of constant length.

We are trying to emulate the common civil calendar here, and in places
that observe DST, days are *not* of constant length. If you don't like
this, why are you using the timestamp-with-time-zone datatype (or at
least, why are you using it with a DST-aware zone setting)?

timestamp-without-time-zone will continue to behave as it always has,
so that seems to me to offer a sufficient out for people who really
truly do not want DST-aware calculations.

regards, tom lane

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