Re: timestamp with time zone a la sql99

On Fri, 22 Oct 2004, Tom Lane wrote:

> As far as I can tell, Dennis is planning slavish adherence to the spec,
> which will mean that the datatype is unable to cope effectively with
> daylight-savings issues.  So I'm unconvinced that it will be very
> helpful to you for remembering local time in addition to true
> (universal) time.

And exactly what issues is it that you see? The only thing I can think of
is if you have a timestamp and then add an interval to it so we jump past
the daylight saving time change date. Then the new timestamp will keep the
old timezone data of say +01 even though we now have jumped into the
daylight saving period of +02.

If you are just storing actual timestamps then the standard definition
works just fine. If I store '2004-10-22 16:20:04 +02' then that's exactly
what I get back. No problem what so ever. There is no DST problem with 
that.

It's possible that I will introduce some daylight saving bit or something
like that, I'm not sure yet and I will not commit to anything until I've
thought it over. I don't think there are that much of a problem as you
claim however. Could you give a concret example where it will be a
problem?

My current thinking is that storing the time zone value as HH:MM is 
just fine and you avoid all the problems with political changes of when 
the DST is in effect or not.

--
/Dennis Björklund