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Re: BUG #3948: date/time functions returning wrong value

From: Magnus Hagander <magnus(at)hagander(dot)net>
To: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jorge Campins <jrcampins(at)cantv(dot)net>,pgsql-bugs(at)postgresql(dot)org
Subject: Re: BUG #3948: date/time functions returning wrong value
Date: 2008-02-11 08:35:03
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-bugs
On Sun, Feb 10, 2008 at 11:22:53PM -0300, Alvaro Herrera wrote:
> Magnus Hagander wrote:
> > Tom Lane wrote:
> >> This does suggest that we'll need to revisit the win32_tzmap[] list
> >> every so often?
> >
> > Seems so. It's the first time I've heard of a timezone being *added* and  
> > not just changed, but obviously it does happen :-(
> Hmm, was this table manually built?  I think I see a mistake.  It has

Yes. And it's obviously in need of updating.

> two entries for "Mexico Standard Time", one of which (the one at GMT-6)
> is mapped to America/Mexico_City (which I think would be correct), and
> the other at America/La_Paz (the one at -7).  This latter one I think is

Yes, that's clearly a mistake :-( It'll only ever use the first one

What's in the database is one called "Mexico Stanadrd Time" and another one
called "Mexico Standard Time 2". We're missing the "2" there.

> It's hard to tell though -- I am not sure how does Windows define
> timezones.  I have always been annoyed by the fact that Chilean timezone
> is nowhere near it's database (I think the closest is Bogota, but it's
> really bogus because it's not even in the same hemisphere).  Fortunately
> this means there's no bogus entry for Chile in this struct ...

My TZ database has an entry for Santiago... AFAIK, that's in Chile? -04?
Took me less than 30 seconds to find in the GUI for the Timezone settings.

The internal entry name is "Pacific SA Standad Time", which we map to

Is that actually bogus?

> I think what I conclude from this is that Windows TZ database is so
> bogus that we should avoid trying to rely on it -- I say if the user
> does not set "timezone" in postgresql.conf, refuse to start.

While there are a lot of bogus things about the Windows TZ database, that's
not one of them. (the bogusness mostly deals with them not properly
tracking changes in DST rules over time - they are only interesetd in rules
that are in force *today*)


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