From: Jim C. Nasby <jim@nasby.net>
To: Bruce Momjian <bruce@momjian.us>
Cc: Jim Nasby <jimn@enterprisedb.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: gdavis@refractions.net
Cc: pgsql-sql@postgresql.org
Cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp subtraction (was Re: formatting intervals with to_char)
Date: Fri, 23 Feb 2007 10:24:27 -0600
Message-ID: <20070223162426.GI19527@nasby.net> (raw)
In-Reply-To: <200702210107.l1L17Bm21179@momjian.us>
References: <DB91DDA2-F0F2-42CF-B5E8-A481E622F1CD@enterprisedb.com>
<200702210107.l1L17Bm21179@momjian.us>
Yes, but if it was '2004-01-02 01:00:00'-'2004-01-01 00:00:00' it should
return 25:00:00, not 1 day 1:00.
I agree with Tom that this should be changed; I'm just arguing that we
might well need a backwards-compatibility solution for a while. At the
very least we'd need to make this change very clear to users.
On Tue, Feb 20, 2007 at 08:07:11PM -0500, Bruce Momjian wrote:
>
> One problem with removing justify_hours() is that this is going to
> return '24:00:00', rather than '1 day:
>
> test=> select '2004-01-02 00:00:00'::timestamptz - '2004-01-01
> 00:00:00'::timestamptz;
> ?column?
> ----------
> 24:00:00
> (1 row)
>
> ---------------------------------------------------------------------------
>
> Jim Nasby wrote:
> > On Oct 5, 2006, at 11:50 AM, Tom Lane wrote:
> > > regression=# select ('2006-09-15 23:59:00'::timestamp - '2006-09-01
> > > 09:30:41'::timestamp);
> > > ?column?
> > > ------------------
> > > 14 days 14:28:19
> > > (1 row)
> > >
> > > should be reporting '350:28:19' instead.
> > >
> > > This is a hack that was done to minimize the changes in the regression
> > > test expected outputs when we changed type interval from months/
> > > seconds
> > > to months/days/seconds. But I wonder whether it wasn't a dumb idea.
> > > It is certainly inconsistent, as noted in the code comments.
> > >
> > > I'm tempted to propose that we remove the justify_hours call, and tell
> > > anyone who really wants the old results to apply justify_hours() to
> > > the
> > > subtraction result for themselves. Not sure what the fallout would
> > > be,
> > > though.
> >
> > I suspect there's applications out there that are relying on that
> > being nicely formated for display purposes.
> >
> > I agree it should be removed, but we might need a form of backwards
> > compatibility for a version or two...
> > --
> > Jim Nasby jimn@enterprisedb.com
> > EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
> >
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 3: Have you checked our extensive FAQ?
> >
> > http://www.postgresql.org/docs/faq
>
> --
> Bruce Momjian <bruce@momjian.us> http://momjian.us
> EnterpriseDB http://www.enterprisedb.com
>
> + If your life is a hard drive, Christ can be your backup. +
>
> ---------------------------(end of broadcast)---------------------------
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--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
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To: pgsql-sql@postgresql.org
Cc: jim@nasby.net, bruce@momjian.us, jimn@enterprisedb.com, tgl@sss.pgh.pa.us, gdavis@refractions.net, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp subtraction (was Re: formatting intervals with to_char)
In-Reply-To: <20070223162426.GI19527@nasby.net>
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