mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-27 08:39:28 +08:00
Code Issues Packages Projects Releases Wiki Activity
ae36e0d589
postgresql/doc/TODO.detail/timezone
Bruce Momjian 32f4ae568c Add TODO.detail of standard timezone data type.
2005-06-05 00:18:42 +00:00

2830 lines
134 KiB
Plaintext
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

From pgsql-hackers-owner+M60207=pgman=candle.pha.pa.us@postgresql.org Thu Oct 21 07:25:41 2004
Return-path: <pgsql-hackers-owner+M60207=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9LBPdf26430
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 07:25:40 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 0548B32A593
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 12:25:37 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 74257-06 for <pgman@candle.pha.pa.us>;
Thu, 21 Oct 2004 11:25:33 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id B0DB532A544
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 12:25:36 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 1124A329FAB
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Thu, 21 Oct 2004 12:23:00 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 70900-09
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Thu, 21 Oct 2004 11:22:43 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 301C532A301
for <pgsql-hackers@postgresql.org>; Thu, 21 Oct 2004 12:22:43 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP id A022C8467
for <pgsql-hackers@postgresql.org>; Thu, 21 Oct 2004 13:22:40 +0200 (CEST)
Date: Thu, 21 Oct 2004 13:22:40 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: pgsql-hackers@postgresql.org
Subject: [HACKERS] timestamp with time zone a la sql99
Message-ID: <Pine.LNX.4.44.0410211300430.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
I've made a partial implementation of a datatype "timestamp with time
zone" as described in the sql standard. The current type "timestamptz"
does not store the time zone as a standard one should do. So I've made a
new type I've called timestampstdtz that does store the time zone as the
standard demands.
Let me show a bit of what currently works in my implementation:
dennis=# CREATE TABLE foo (
a timestampstdtz,
primary key (a)
);
dennis=# INSERT INTO foo VALUES ('1993-02-04 13:00 UTC');
dennis=# INSERT INTO foo VALUES ('1999-06-01 14:00 CET');
dennis=# INSERT INTO foo VALUES ('2003-08-21 15:00 PST');
dennis=# SELECT a FROM foo;
a
------------------------
1993-02-04 13:00:00+00
1999-06-01 14:00:00+01
2003-08-21 15:00:00-08
dennis=# SELECT a AT TIME ZONE 'CET' FROM foo;
timezone
------------------------
1993-02-04 14:00:00+01
1999-06-01 14:00:00+01
2003-08-22 00:00:00+01
My plan is to make a GUC variable so that one can tell PG that constructs
like "timestamp with time zone" will map to timestampstdtz instead of
timestamptz (some old databases might need the old so unless we want to
break old code this is the easiest solution I can find).
I've made an implicit cast from timestampstdtz to timestamptz that just
forgets about the time zone. In the other direction I've made an
assignment cast that make a timestamp with time zone 0 (that's what a
timestamptz is anyway). Would it be possible to make it implicit in both
directions? I currently don't think that you want that, but is it
possible?
With the implicit cast in place I assume it would be safe to change
functions like now() to return a timestampstdtz? I've not tried yet but I
will. As far as I can tell the cast would make old code that use now() to
still work as before.
Any comments before I invest more time into this subject?
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
From pgsql-hackers-owner+M60208=pgman=candle.pha.pa.us@postgresql.org Thu Oct 21 10:34:36 2004
Return-path: <pgsql-hackers-owner+M60208=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9LEYYf08049
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 10:34:35 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 34B0F32A2AB
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 15:34:30 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 38287-03 for <pgman@candle.pha.pa.us>;
Thu, 21 Oct 2004 14:34:26 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 6A38132A1B6
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 15:34:29 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 535FE32A9EE
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Thu, 21 Oct 2004 15:29:17 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 34535-09
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Thu, 21 Oct 2004 14:29:10 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 41E4F32A9D6
for <pgsql-hackers@postgresql.org>; Thu, 21 Oct 2004 15:29:12 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9LET86O015233;
Thu, 21 Oct 2004 10:29:10 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410211300430.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410211300430.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Thu, 21 Oct 2004 13:22:40 +0200"
Date: Thu, 21 Oct 2004 10:29:07 -0400
Message-ID: <15232.1098368947@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> I've made a partial implementation of a datatype "timestamp with time
> zone" as described in the sql standard. The current type "timestamptz"
> does not store the time zone as a standard one should do.
I'm aware that there are aspects of the spec behavior that appear to
require that, but is it really an improvement over the implementation
we have? This is an area in which the standard is pretty brain-dead
--- the entire concept of a "time with time zone" datatype is rather
suspect, for instance.
In particular, I wonder how you will handle daylight-savings issues.
The spec definition seems to preclude doing anything intelligent with
DST, as they equate a timezone with a fixed offset from UTC. That's
not how it works in (large parts of) the real world.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 6: Have you searched our list archives?
http://archives.postgresql.org
From pgsql-hackers-owner+M60210=pgman=candle.pha.pa.us@postgresql.org Thu Oct 21 11:08:02 2004
Return-path: <pgsql-hackers-owner+M60210=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9LF7xf13992
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 11:08:00 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id AEBEE32AB8E
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 16:07:55 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 51273-03 for <pgman@candle.pha.pa.us>;
Thu, 21 Oct 2004 15:07:55 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 506C832AB6A
for <pgman@candle.pha.pa.us>; Thu, 21 Oct 2004 16:07:55 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 59130329F96
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Thu, 21 Oct 2004 16:02:14 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 48602-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Thu, 21 Oct 2004 15:01:59 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 8ED0932A095
for <pgsql-hackers@postgresql.org>; Thu, 21 Oct 2004 16:01:54 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id D08B88467; Thu, 21 Oct 2004 17:01:52 +0200 (CEST)
Date: Thu, 21 Oct 2004 17:01:52 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <15232.1098368947@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410211637560.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Thu, 21 Oct 2004, Tom Lane wrote:
> > I've made a partial implementation of a datatype "timestamp with time
> > zone" as described in the sql standard. The current type "timestamptz"
> > does not store the time zone as a standard one should do.
>
> I'm aware that there are aspects of the spec behavior that appear to
> require that, but is it really an improvement over the implementation
> we have?
Improvement and improvement. The actual time value is of course the same
(the utc part of a timestamp) and the only thing extra you get is that the
time zone is stored. The extra information you do have now, when stored in
this way, is that you store both a utc time and a local time. Will any
application ever need that? Who knows? I think it makes sense and is an
easier model to think about then what pg uses today. So I would use it
even if it means using 2 bytes more storage then what timestamptz do
Just that it is standard also makes it useful. The more things of the
standard we support the easier it is to move between databases. This is
important to me.
I also want to make a general statement that I think that whenever we use
standard syntax we should give it a standard semantics. I don't mind
extensions at all, but as much as we can we should make sure that they
don't clash with standard syntax and semantics.
> This is an area in which the standard is pretty brain-dead
> --- the entire concept of a "time with time zone" datatype is rather
> suspect, for instance.
I havn't look that much at "time with time zone" yet, just timestamps.
I can't see why time with time zone should not also be supported. I can't
really imagine it being used without a date, but if someone wants to store
timestamps as a date+time with time zone, then why not. It would be extra
work tu is it instead of a timestamp (especially for cases where the time
wraps over to the prev/next day), but hey.
> In particular, I wonder how you will handle daylight-savings issues.
> The spec definition seems to preclude doing anything intelligent with
> DST, as they equate a timezone with a fixed offset from UTC. That's
> not how it works in (large parts of) the real world.
The tz in the standard is a offset from utc, yes. So when you store a
value you tell it what offset you use. If you are using daylight-savings
time it might be +02 and if not dst it might be +01. What else would you
want to do with it? It's not like you can do anything else with it in pg
as of today, can you?
The stored tz does not say what region of the globe you are in, it says
the distance away from utc in minutes that you are. I could imagine
another datatype that stores the time zone as name, but that's not what
timestamp with time zone does.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 8: explain analyze is your friend
From pgsql-hackers-owner+M60232=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 08:43:06 2004
Return-path: <pgsql-hackers-owner+M60232=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MCh4f16646
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 08:43:04 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id D389532A4BA
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 13:42:58 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 01914-09 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 12:42:51 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 82BD832A4B3
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 13:42:58 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 05C2132A3F5
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 13:39:37 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 03281-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 12:39:20 +0000 (GMT)
Received: from lakermmtao07.cox.net (lakermmtao07.cox.net [68.230.240.32])
by svr1.postgresql.org (Postfix) with ESMTP id 1971732A32B
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 13:39:26 +0100 (BST)
Received: from [192.168.0.9] (really [24.250.237.182])
by lakermmtao07.cox.net
(InterMail vM.6.01.03.04 201-2131-111-106-20040729) with ESMTP
id <20041022123912.IJSP14063.lakermmtao07.cox.net@[192.168.0.9]>;
Fri, 22 Oct 2004 08:39:12 -0400
From: Robert Treat <xzilla@users.sourceforge.net>
To: Dennis Bjorklund <db@zigo.dhs.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Date: Fri, 22 Oct 2004 08:37:33 -0400
User-Agent: KMail/1.6.2
cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org
References: <Pine.LNX.4.44.0410211637560.2015-100000@zigo.dhs.org>
In-Reply-To: <Pine.LNX.4.44.0410211637560.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-ID: <200410220837.33886.xzilla@users.sourceforge.net>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Thursday 21 October 2004 11:01, Dennis Bjorklund wrote:
> On Thu, 21 Oct 2004, Tom Lane wrote:
> > I'm aware that there are aspects of the spec behavior that appear to
> > require that, but is it really an improvement over the implementation
> > we have?
>
> Improvement and improvement. The actual time value is of course the same
> (the utc part of a timestamp) and the only thing extra you get is that the
> time zone is stored. The extra information you do have now, when stored in
> this way, is that you store both a utc time and a local time. Will any
> application ever need that? Who knows? I think it makes sense and is an
> easier model to think about then what pg uses today. So I would use it
> even if it means using 2 bytes more storage then what timestamptz do
>
In a fit of early morning, pre-coffee thoughts, I'm thinking this might be
just what I've been looking for. In one of my apps we take calls from around
the country for customers and store the time that call came in. Unfortunately
we need to know things like how many calls did we take in an hour across
customers, but also how many calls did we take at 6AM local time to the
customer. The way PostgreSQL works now, you have to store some extra bits
of info in another column and then reassemble it to be able to determine
those two queries, but it sounds like your timestampstdtz would allow that
information to be stored together, as it should be.
--
Robert Treat
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL
---------------------------(end of broadcast)---------------------------
TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org
From pgsql-hackers-owner+M60235=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 10:18:44 2004
Return-path: <pgsql-hackers-owner+M60235=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MEIhf03000
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 10:18:44 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 63ACB329FE3
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:18:38 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 35128-09 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 14:18:30 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 3439A329E73
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:18:38 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id C332832A5AA
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 15:13:18 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 32986-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 14:13:09 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id E7E6F32A576
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 15:13:16 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9MEDIA4006541;
Fri, 22 Oct 2004 10:13:18 -0400 (EDT)
To: Robert Treat <xzilla@users.sourceforge.net>
cc: Dennis Bjorklund <db@zigo.dhs.org>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410220837.33886.xzilla@users.sourceforge.net>
References: <Pine.LNX.4.44.0410211637560.2015-100000@zigo.dhs.org> <200410220837.33886.xzilla@users.sourceforge.net>
Comments: In-reply-to Robert Treat <xzilla@users.sourceforge.net>
message dated "Fri, 22 Oct 2004 08:37:33 -0400"
Date: Fri, 22 Oct 2004 10:13:18 -0400
Message-ID: <6540.1098454398@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Robert Treat <xzilla@users.sourceforge.net> writes:
> In a fit of early morning, pre-coffee thoughts, I'm thinking this might be
> just what I've been looking for. In one of my apps we take calls from around
> the country for customers and store the time that call came in. Unfortunately
> we need to know things like how many calls did we take in an hour across
> customers, but also how many calls did we take at 6AM local time to the
> customer. The way PostgreSQL works now, you have to store some extra bits
> of info in another column and then reassemble it to be able to determine
> those two queries, but it sounds like your timestampstdtz would allow that
> information to be stored together, as it should be.
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.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60237=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 10:33:04 2004
Return-path: <pgsql-hackers-owner+M60237=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MEX3f05134
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 10:33:03 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id AB3B432A907
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:32:57 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 42366-04 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 14:32:49 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 28B5E32A6BE
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:32:56 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 5366A32A923
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 15:28:12 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 41328-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 14:28:03 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 0277A32A916
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 15:28:10 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 336C88467; Fri, 22 Oct 2004 16:28:12 +0200 (CEST)
Date: Fri, 22 Oct 2004 16:28:12 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: Robert Treat <xzilla@users.sourceforge.net>,
<pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <6540.1098454398@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410221615150.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
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 Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60240=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 10:58:26 2004
Return-path: <pgsql-hackers-owner+M60240=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MEwOf10545
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 10:58:24 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 8F3BC32A0AC
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:58:18 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 53613-02 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 14:58:10 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 32CD532A0A2
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:58:18 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 65D9932A0AC
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 15:54:30 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 49578-08
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 14:54:12 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id A7D2A329FB7
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 15:54:17 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9MEsJsB006995;
Fri, 22 Oct 2004 10:54:19 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Robert Treat <xzilla@users.sourceforge.net>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410221615150.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410221615150.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Fri, 22 Oct 2004 16:28:12 +0200"
Date: Fri, 22 Oct 2004 10:54:19 -0400
Message-ID: <6994.1098456859@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> 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.
Isn't that sufficient? You can't design a datatype by thinking only of
the data values it stores; you have to think about the operations you
intend to provide as well. A non-DST-capable timestamp datatype is
inherently a few bricks shy of a load. (BTW we really need to fix
the interval type as well...)
At bottom, what I want to be able to do is say
'2004-10-22 10:50:16.916003 America/New_York'
and have the datatype preserve *all* of the information in that. You
are complaining because the existing type only remembers the equivalent
universal time and not the timezone spec. Why should I be satisfied if
it stores only the GMT offset and not the knowledge of which timezone
this really is?
> 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.
This is fundamentally misguided. Time zones *are* political whether you
like it or not, and people *do* expect DST-awareness whether you like it
or not. If you still use any computer systems that need to be reset
twice a year because their designers thought DST was not their problem,
don't you roundly curse them every time you have to do it?
If you were planning to store a real (potentially DST-aware) timezone
spec in the data values, I'd be happy. But storing a fixed GMT offset
is going to be a step backwards compared to existing functionality. The
fact that it's sufficient to satisfy the DST-ignorant SQL spec does not
make it a reasonable design for the real world.
One way to do this would be to create a system catalog with entries for
all known timezones, and then represent timestamptz values as universal
time plus an OID from that catalog. There are other ways that small
integer codes could be mapped to timezones of course.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
From pgsql-hackers-owner+M60239=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 10:49:13 2004
Return-path: <pgsql-hackers-owner+M60239=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MEnCf08566
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 10:49:12 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 5B4D432A0A2
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:49:07 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 50773-01 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 14:48:59 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 230EA329F96
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 15:49:07 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 7CCE332A20E
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 15:46:10 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 45902-10
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 14:45:52 +0000 (GMT)
Received: from wolff.to (wolff.to [66.93.249.74])
by svr1.postgresql.org (Postfix) with SMTP id 30F0F32A1FA
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 15:45:58 +0100 (BST)
Received: (qmail 17526 invoked by uid 500); 22 Oct 2004 14:56:44 -0000
Date: Fri, 22 Oct 2004 09:56:44 -0500
From: Bruno Wolff III <bruno@wolff.to>
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Tom Lane <tgl@sss.pgh.pa.us>, Robert Treat <xzilla@users.sourceforge.net>,
pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Message-ID: <20041022145644.GA17238@wolff.to>
Mail-Followup-To: Dennis Bjorklund <db@zigo.dhs.org>,
Tom Lane <tgl@sss.pgh.pa.us>,
Robert Treat <xzilla@users.sourceforge.net>,
pgsql-hackers@postgresql.org
References: <6540.1098454398@sss.pgh.pa.us> <Pine.LNX.4.44.0410221615150.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Pine.LNX.4.44.0410221615150.2015-100000@zigo.dhs.org>
User-Agent: Mutt/1.5.6i
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Fri, Oct 22, 2004 at 16:28:12 +0200,
Dennis Bjorklund <db@zigo.dhs.org> wrote:
> 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.
I think for just storing values you are fine. When it comes to adding or
subtracting intervals you might get some unexpected results.
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60253=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 14:44:05 2004
Return-path: <pgsql-hackers-owner+M60253=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MIi3f14607
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 14:44:03 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id B336CEAEDAF
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 19:43:39 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 21148-08 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 18:43:46 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 4FC1AEAEDAB
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 19:43:39 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 178B1EAEF44
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 19:38:04 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 20287-01
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 18:38:00 +0000 (GMT)
Received: from www.postgresql.com (www.postgresql.com [200.46.204.209])
by svr1.postgresql.org (Postfix) with ESMTP id D1F79EAEE4F
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 19:37:45 +0100 (BST)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by www.postgresql.com (Postfix) with ESMTP id 358575A1CED
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 16:34:33 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 89B7E8467; Fri, 22 Oct 2004 17:34:19 +0200 (CEST)
Date: Fri, 22 Oct 2004 17:34:19 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: Robert Treat <xzilla@users.sourceforge.net>,
<pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <6994.1098456859@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410221714500.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Fri, 22 Oct 2004, Tom Lane wrote:
> At bottom, what I want to be able to do is say
> '2004-10-22 10:50:16.916003 America/New_York'
Yes, that's what we said in the last mail and I think there is a value in
having something like this.
> universal time and not the timezone spec. Why should I be satisfied if
> it stores only the GMT offset and not the knowledge of which timezone
> this really is?
You don't need to be satisfied with it. I think a type like the above
would be fine to have. It should however not be called "TIMESTAMP WITH
TIME ZONE" because there is already a definition of that type. We can not
hijack standard types. I would not mind a type like TIMESTAMP WITH TIME
ZONE NAME (or some other name). I could even imagine that I could
implement something like that one day.
> > 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.
>
> This is fundamentally misguided. Time zones *are* political whether you
> like it or not, and people *do* expect DST-awareness whether you like it
> or not.
And I never said that time zones are not political, just that HH:MM is a
usable approximation that works fairly well.
> But storing a fixed GMT offset is going to be a step backwards compared
> to existing functionality.
It's not a step backwards since you can do everything you can do with the
current type plus a little bit more. It's however not a step to the
datatype discussed above.
> One way to do this would be to create a system catalog with entries for
> all known timezones, and then represent timestamptz values as universal
> time plus an OID from that catalog. There are other ways that small
> integer codes could be mapped to timezones of course.
This is just fine. You try to make it sound like I am against such a
datatype, I am not. It's however not the datatype that we can expect
applications and other databases to use. So why should we settle for only
that type. Just because you can make a perfect datatype it doesn't mean
that the standard datatype should just be ignored.
What would you store when the user supplies a timestamp like '2004-10-22
17:21:00 +0200'. Should you reject that because you don't know the
time zone name? So your datatype will not work for applications that try
to be compatable with many databases by using the standard?
Maybe one could make a datatype called TIMESTAMP WITH TIME ZONE that can
accept both HH:MM and TimeZoneName. Whenever you store values with HH:MM
time zones you will get the same problem when you add an interval as the
standard type has.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 8: explain analyze is your friend
From pgsql-hackers-owner+M60266=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 17:04:46 2004
Return-path: <pgsql-hackers-owner+M60266=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9ML4jf06676
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 17:04:45 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id C13F9EAE46B
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:04:20 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 66740-03 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 21:04:28 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 75764EAE1A2
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:04:20 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 2E4AFEAE486
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 22:01:22 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 63290-09
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 21:01:22 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 88B3FEAE492
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 22:01:13 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9ML1WrB018877;
Fri, 22 Oct 2004 17:01:34 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Robert Treat <xzilla@users.sourceforge.net>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410221714500.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410221714500.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Fri, 22 Oct 2004 17:34:19 +0200"
Date: Fri, 22 Oct 2004 17:01:32 -0400
Message-ID: <18876.1098478892@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> You don't need to be satisfied with it. I think a type like the above
> would be fine to have. It should however not be called "TIMESTAMP WITH
> TIME ZONE" because there is already a definition of that type. We can not
> hijack standard types.
Sure we can, as long as they are upward compatible with the standard
behavior. The spec says you can put a numeric-GMT-offset zone in and
get a numeric-GMT-offset zone out. We can do that and also support
named, possibly DST-aware zones. This seems a whole lot better to me
than having two different types (the idea of a GUC variable to choose
which one is selected by a given type name is just horrid).
>> But storing a fixed GMT offset is going to be a step backwards compared
>> to existing functionality.
> It's not a step backwards since you can do everything you can do with the
> current type plus a little bit more.
... except get useful answers from interval addition ...
> What would you store when the user supplies a timestamp like '2004-10-22
> 17:21:00 +0200'. Should you reject that because you don't know the
> time zone name?
You are attacking a straw man.
We have put a great deal of work into 8.0 to add the ability to support
real-world zones fully. We did not import src/timezone because we
needed it to implement the SQL spec; we did so because we needed it to
implement what real users want. We are not fully there yet (can't do AT
TIME ZONE conversions with all zones yet, for instance) but I am hoping
to be there by 8.1. It would be folly to invent a timestamp with time
zone type that is going in the other direction while we are trying to
bring the rest of the system up to full speed by allowing all timezone
kinds everywhere.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60267=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 17:22:15 2004
Return-path: <pgsql-hackers-owner+M60267=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MLMEf09207
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 17:22:14 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 0B2D7EAE4AC
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:21:49 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 70387-04 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 21:21:56 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 0930BEAE4AA
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:21:48 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 292E8EAC955
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 22:18:05 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 68984-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 21:18:04 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id A3C4DEAE489
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 22:17:51 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 065508469; Fri, 22 Oct 2004 23:18:08 +0200 (CEST)
Date: Fri, 22 Oct 2004 23:18:07 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: Robert Treat <xzilla@users.sourceforge.net>,
<pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <18876.1098478892@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410222306560.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Fri, 22 Oct 2004, Tom Lane wrote:
> than having two different types (the idea of a GUC variable to choose
> which one is selected by a given type name is just horrid).
That is needed no matter what change you do if you want old programs that
use the current timestamp with time zone to work. Today you don't get back
the same time zone as you insert, programs might depend on that.
> We are not fully there yet (can't do AT TIME ZONE conversions with all
> zones yet, for instance)
Why is that? When one start with a utc value, performing a AT TIME ZONE
operation doesn't look so complicated.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
From pgsql-hackers-owner+M60268=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 17:41:36 2004
Return-path: <pgsql-hackers-owner+M60268=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MLfYf12294
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 17:41:35 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id EFAEAEAE4AA
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:41:08 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 75185-08 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 21:41:16 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 311A7EAE4AF
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:41:08 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id AC0CFEAE486
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 22:38:14 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 76579-03
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 21:38:13 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id BD0AAEAD7E2
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 22:38:03 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9MLcOnT019118;
Fri, 22 Oct 2004 17:38:25 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Robert Treat <xzilla@users.sourceforge.net>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410222306560.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410222306560.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Fri, 22 Oct 2004 23:18:07 +0200"
Date: Fri, 22 Oct 2004 17:38:24 -0400
Message-ID: <19117.1098481104@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> On Fri, 22 Oct 2004, Tom Lane wrote:
>> than having two different types (the idea of a GUC variable to choose
>> which one is selected by a given type name is just horrid).
> That is needed no matter what change you do if you want old programs that
> use the current timestamp with time zone to work. Today you don't get back
> the same time zone as you insert, programs might depend on that.
[ shrug... ] We've made much larger changes than that in the name of
standards compliance. In practice I think the majority of apps are
working in contexts where they will get back the same zone as they
inserted, if they inserted a zone explicitly at all, so the risk of
breakage is not that high. Having a GUC variable that changes the
semantics underneath you is *much* riskier, to judge by past experience.
>> We are not fully there yet (can't do AT TIME ZONE conversions with all
>> zones yet, for instance)
> Why is that?
Because it's not done yet. There's a set of GMT-offset-only zone names
wired into the datetime code (look in the "datetime token table") and
those are what AT TIME ZONE knows how to deal with. We need to unify
that old stuff with the src/timezone code, but we ran out of time to do
it in 8.0.
The way I see it, we have three sorts of zones to deal with: fixed
numeric offsets from UTC, names that represent fixed offsets (eg, "EST"
is the same as UTC-5), and names that represent DST-variable offsets
(eg, "EST5EDT"). For what are now entirely historical reasons, various
parts of the system cope with different subsets of these three types.
I want to get to a state where you can use any of them in any context
and it Just Works. (While we are at it, we need to make the set of
recognized zone names user-configurable; the australian_timezones kluge
satisfies our contributors Down Under, but there are a lot of unhappy
people still, because for instance IST means different things in Israel
and India.)
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
From pgsql-hackers-owner+M60269=pgman=candle.pha.pa.us@postgresql.org Fri Oct 22 17:51:14 2004
Return-path: <pgsql-hackers-owner+M60269=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9MLpCf14192
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 17:51:13 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 43D6BEAE489
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:50:47 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 78632-05 for <pgman@candle.pha.pa.us>;
Fri, 22 Oct 2004 21:50:55 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id EFC45EAE486
for <pgman@candle.pha.pa.us>; Fri, 22 Oct 2004 22:50:46 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 42518EAC955
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Fri, 22 Oct 2004 22:48:36 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 77399-07
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Fri, 22 Oct 2004 21:48:35 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 8BB75EAE46B
for <pgsql-hackers@postgresql.org>; Fri, 22 Oct 2004 22:48:27 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9MLmm1l019192;
Fri, 22 Oct 2004 17:48:48 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Robert Treat <xzilla@users.sourceforge.net>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <19117.1098481104@sss.pgh.pa.us>
References: <Pine.LNX.4.44.0410222306560.2015-100000@zigo.dhs.org> <19117.1098481104@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
message dated "Fri, 22 Oct 2004 17:38:24 -0400"
Date: Fri, 22 Oct 2004 17:48:48 -0400
Message-ID: <19191.1098481728@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
>> That is needed no matter what change you do if you want old programs that
>> use the current timestamp with time zone to work. Today you don't get back
>> the same time zone as you insert, programs might depend on that.
> [ shrug... ] We've made much larger changes than that in the name of
> standards compliance.
BTW, even if you do want output like that, that doesn't make two
datatypes a good idea. It'd be better to add a couple of DateStyle-like
formatting options:
* rotate all timestamps into current TimeZone for display, or not;
* display the timezone numerically, or as originally given.
A DateStyle kind of GUC variable is a lot less dangerous than what you
were proposing, because getting it wrong doesn't mean you have the wrong
data stored in the database ...
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
From pgsql-hackers-owner+M60274=pgman=candle.pha.pa.us@postgresql.org Sat Oct 23 02:11:58 2004
Return-path: <pgsql-hackers-owner+M60274=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9N6Buf20583
for <pgman@candle.pha.pa.us>; Sat, 23 Oct 2004 02:11:57 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id B3D75EAE4AC
for <pgman@candle.pha.pa.us>; Sat, 23 Oct 2004 07:11:22 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 75750-09 for <pgman@candle.pha.pa.us>;
Sat, 23 Oct 2004 06:11:32 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 560D3EADBC0
for <pgman@candle.pha.pa.us>; Sat, 23 Oct 2004 07:11:22 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 9D862EAE4CB
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Sat, 23 Oct 2004 07:08:48 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 77538-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Sat, 23 Oct 2004 06:08:54 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 29BC1EAC8F4
for <pgsql-hackers@postgresql.org>; Sat, 23 Oct 2004 07:08:40 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 846788467; Sat, 23 Oct 2004 08:09:05 +0200 (CEST)
Date: Sat, 23 Oct 2004 08:09:05 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: Robert Treat <xzilla@users.sourceforge.net>,
<pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <18876.1098478892@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410230802200.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Fri, 22 Oct 2004, Tom Lane wrote:
> behavior. The spec says you can put a numeric-GMT-offset zone in and
> get a numeric-GMT-offset zone out. We can do that and also support
> named, possibly DST-aware zones.
So if I understand you correctly you are planning to extend the current
timestamp type to work with both named time zones and HH:MM ones? I didn't
think you wanted the last one since your plan was to store a UTC+OID where
the OID pointed to a named time zone. And I guess that you don't plan to
add 00:00, 00:01, 00:02, ... as named zones with an OID.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 9: the planner will ignore your desire to choose an index scan if your
joining column's datatypes do not match
From pgsql-hackers-owner+M60329=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 12:45:39 2004
Return-path: <pgsql-hackers-owner+M60329=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PGjcf25576
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 12:45:38 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 27F433A4146
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 17:45:35 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 63030-04 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 16:45:34 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id D15153A413C
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 17:45:34 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 4D4653A415D
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 17:43:32 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 60516-10
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 16:43:26 +0000 (GMT)
Received: from davinci.ethosmedia.com (server226.ethosmedia.com [209.128.84.226])
by svr1.postgresql.org (Postfix) with ESMTP id CAB1E3A4170
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 17:43:26 +0100 (BST)
Received: from [63.195.55.98] (account josh@agliodbs.com HELO spooky)
by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8)
with ESMTP id 6553366 for pgsql-hackers@postgresql.org; Mon, 25 Oct 2004 09:44:52 -0700
From: Josh Berkus <josh@agliodbs.com>
Organization: Aglio Database Solutions
To: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Date: Mon, 25 Oct 2004 09:42:38 -0700
User-Agent: KMail/1.6.2
References: <20041022184636.62D39EAEE02@svr1.postgresql.org>
In-Reply-To: <20041022184636.62D39EAEE02@svr1.postgresql.org>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
charset="utf-8"
Message-ID: <200410250942.38212.josh@agliodbs.com>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by candle.pha.pa.us id i9PGjcf25576
X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on
candle.pha.pa.us
X-Spam-Status: No, hits=-4.9 required=5.0 tests=BAYES_00 autolearn=ham
version=2.61
Status: OR
Tom,
> 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.
As somebody who codes calendar apps, I have to say that I have yet to see an
implementation of time zones which is at all useful for this purpose,
including the current implementation. My calendar apps on PostgreSQL 7.4
use "timestamp without time zone" and keep the time zone in a seperate field.
The reason is simple: our current implementation, which does include DST,
does not include any provision for the exceptions to DST -- such as Arizona
-- or for the difference between "1 day" and "24 hours". (Try adding "30
days" to "2004-10-05 10:00 PDT", you'll see what I mean). Nor do I see a
way out of this without raising the complexity, and configurability, level of
timezones significantly.
So if we're going to be broken (at least from the perspective of calendar
applications) we might as well be broken in a spec-compliant way.
--
Josh Berkus
Aglio Database Solutions
San Francisco
---------------------------(end of broadcast)---------------------------
TIP 6: Have you searched our list archives?
http://archives.postgresql.org
From pgsql-hackers-owner+M60334=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 13:56:27 2004
Return-path: <pgsql-hackers-owner+M60334=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PHuQf06230
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 13:56:26 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 024493A3C12
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 18:56:23 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 90234-01 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 17:56:21 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id B12643A3BDD
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 18:56:22 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 038CC3A412E
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 18:54:57 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 89206-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 17:54:54 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 0D5D13A3B06
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 18:54:54 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9PHsrvv021835;
Mon, 25 Oct 2004 13:54:53 -0400 (EDT)
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410250942.38212.josh@agliodbs.com>
References: <20041022184636.62D39EAEE02@svr1.postgresql.org> <200410250942.38212.josh@agliodbs.com>
Comments: In-reply-to Josh Berkus <josh@agliodbs.com>
message dated "Mon, 25 Oct 2004 09:42:38 -0700"
Date: Mon, 25 Oct 2004 13:54:53 -0400
Message-ID: <21834.1098726893@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Josh Berkus <josh@agliodbs.com> writes:
> The reason is simple: our current implementation, which does include DST,
> does not include any provision for the exceptions to DST -- such as Arizona
Say what?
regression=# set timezone to 'MST7MDT';
SET
regression=# select now();
now
-------------------------------
2004-10-25 11:52:47.093538-06
(1 row)
regression=# set timezone to 'US/Arizona';
SET
regression=# select now();
now
-------------------------------
2004-10-25 10:52:49.441559-07
(1 row)
> -- or for the difference between "1 day" and "24 hours". (Try adding "30
> days" to "2004-10-05 10:00 PDT", you'll see what I mean).
This is the point about how interval needs to treat "day" as different
from "24 hours". I agree with that; the fact that it's not done already
is just a reflection of limited supply of round tuits. I think it's
orthogonal to the question of how flexible timestamp with time zone
needs to be, though.
> Nor do I see a way out of this without raising the complexity, and
> configurability, level of timezones significantly.
This does not seem to me to be an argument why timestamp with time zone
ought to be incapable of dealing with DST-aware time zones. That simply
guarantees that calendar apps won't be able to use the datatype. If
they still can't use it when it can do that, then we can look at the
next blocking factor.
> So if we're going to be broken (at least from the perspective of calendar
> applications) we might as well be broken in a spec-compliant way.
I have not said that we can't comply with the spec. I have said that
our ambitions need to be higher than merely complying with the spec.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60335=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 14:08:52 2004
Return-path: <pgsql-hackers-owner+M60335=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PI8of08458
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 14:08:51 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id EB0003A4181
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:08:47 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 94404-01 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 18:08:46 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 984283A417A
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:08:47 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 058F13A3B6E
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 19:06:53 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 91573-10
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 18:06:42 +0000 (GMT)
Received: from davinci.ethosmedia.com (server226.ethosmedia.com [209.128.84.226])
by svr1.postgresql.org (Postfix) with ESMTP id B6FB73A3AC2
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 19:06:43 +0100 (BST)
Received: from [64.81.245.111] (account josh@agliodbs.com HELO temoku.sf.agliodbs.com)
by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8)
with ESMTP id 6553760; Mon, 25 Oct 2004 11:08:08 -0700
From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Date: Mon, 25 Oct 2004 11:08:52 -0700
User-Agent: KMail/1.6.2
cc: Tom Lane <tgl@sss.pgh.pa.us>
References: <20041022184636.62D39EAEE02@svr1.postgresql.org> <200410250942.38212.josh@agliodbs.com> <21834.1098726893@sss.pgh.pa.us>
In-Reply-To: <21834.1098726893@sss.pgh.pa.us>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
charset="utf-8"
Content-Transfer-Encoding: 7bit
Message-ID: <200410251108.52164.josh@agliodbs.com>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Tom,
> regression=# set timezone to 'US/Arizona';
> SET
> regression=# select now();
> now
> -------------------------------
> 2004-10-25 10:52:49.441559-07
Wow! When did that get fixed? How do I keep track of this stuff if you
guys keep fixing it? ;-)
Of course, it would be very helpful if the result above could display
"Arizona" instead of the non-specific "-07", but I'm pretty sure that's
already a TODO.
> This is the point about how interval needs to treat "day" as different
> from "24 hours". I agree with that; the fact that it's not done already
> is just a reflection of limited supply of round tuits.
Well, when I first brought up the issue (2001) I was shot down on the basis of
spec-compliance, since SQL92 recognizes only Year/Month and
Day/Hour/Minute/etc. partitions. Glad it's up for consideration again.
Come to think of it, it was Thomas Lockhart who shot down the idea of fixing
Interval, and he's retired now ...
> This does not seem to me to be an argument why timestamp with time zone
> ought to be incapable of dealing with DST-aware time zones. That simply
> guarantees that calendar apps won't be able to use the datatype. If
> they still can't use it when it can do that, then we can look at the
> next blocking factor.
That's definitely a progressive attitude .... pardon me for being pessimistic.
> I have not said that we can't comply with the spec. I have said that
> our ambitions need to be higher than merely complying with the spec.
Hmmm ... well, does the spec specifically prohibit DST, or just leave it out?
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
From pgsql-hackers-owner+M60336=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 14:21:12 2004
Return-path: <pgsql-hackers-owner+M60336=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PILAf10029
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 14:21:11 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 96C283A3B0E
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:21:07 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 96954-06 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 18:21:06 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 528B73A3B06
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:21:07 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id E010F3A4192
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 19:19:46 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 96137-04
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 18:19:41 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id A1BDA3A4190
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 19:19:42 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9PIJegg022094;
Mon, 25 Oct 2004 14:19:40 -0400 (EDT)
To: josh@agliodbs.com
cc: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251108.52164.josh@agliodbs.com>
References: <20041022184636.62D39EAEE02@svr1.postgresql.org> <200410250942.38212.josh@agliodbs.com> <21834.1098726893@sss.pgh.pa.us> <200410251108.52164.josh@agliodbs.com>
Comments: In-reply-to Josh Berkus <josh@agliodbs.com>
message dated "Mon, 25 Oct 2004 11:08:52 -0700"
Date: Mon, 25 Oct 2004 14:19:40 -0400
Message-ID: <22093.1098728380@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Josh Berkus <josh@agliodbs.com> writes:
>> regression=# set timezone to 'US/Arizona';
>> SET
>> regression=# select now();
>> now
>> -------------------------------
>> 2004-10-25 10:52:49.441559-07
> Wow! When did that get fixed? How do I keep track of this stuff if you
> guys keep fixing it? ;-)
> Of course, it would be very helpful if the result above could display
> "Arizona" instead of the non-specific "-07", but I'm pretty sure that's
> already a TODO.
Well, that is *exactly what I'm talking about*. I want timestamp with
time zone to carry "US/Arizona" not just "-07". Obviously there needs
to be some option to get the latter displayed when that's all you want,
but internally a value of the datatype needs to be able to carry full
knowledge of which timezone it's supposed to be in. Dumbing that down
to a simple numeric GMT offset isn't good enough.
>> I have not said that we can't comply with the spec. I have said that
>> our ambitions need to be higher than merely complying with the spec.
> Hmmm ... well, does the spec specifically prohibit DST, or just leave it out?
It just doesn't talk about it AFAICS.
To comply with the spec we definitely need to be *able* to support
timezone values that are simple numeric GMT offsets. But I think we
ought also to be able to store values that are references to any of
the zic database entries. This looks to me like a straightforward
extension of the spec.
We went to all the trouble of importing src/timezone in order that we
could make a significant upgrade in our timezone capability, and now
it's time to take the steps that that enables. Before we were limited
to the lowest-common-denominator of the libc timezone routines on all
our different platforms, but now we are not...
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 6: Have you searched our list archives?
http://archives.postgresql.org
From pgsql-hackers-owner+M60337=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 14:28:59 2004
Return-path: <pgsql-hackers-owner+M60337=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PISvf11118
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 14:28:58 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 928B13A3B43
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:28:54 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 00197-04 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 18:28:53 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 518C33A3B06
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:28:54 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 3AA743A3B0E
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 19:27:17 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 99849-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 18:27:07 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id B62843A418A
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 19:27:01 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 5AD8C8467; Mon, 25 Oct 2004 20:26:59 +0200 (CEST)
Date: Mon, 25 Oct 2004 20:26:59 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251108.52164.josh@agliodbs.com>
Message-ID: <Pine.LNX.4.44.0410252019320.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Josh Berkus wrote:
> Hmmm ... well, does the spec specifically prohibit DST, or just leave it
> out?
It doesn't discuss it. According to the spec a timestamp with time zone is
a UTC value + a HH:MM offset from GMT. And intervals in the spec is either
a year-month value or a day-time value. One can only compare year-month
values with each other and day-time values with each other. So they avoid
the problem of the how many days is a month by not allowing it.
The spec is not a full solution, it's also not a useless solution. I'm
happy as long as the spec is a subset of what pg implements. If not then I
would like to be able to have both but with different names or something
similar (but I think that should not be needed).
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60338=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 14:54:31 2004
Return-path: <pgsql-hackers-owner+M60338=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PIsUf15052
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 14:54:30 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 3F9063A41BC
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:54:27 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 09766-01 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 18:54:25 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id E25B63A41BA
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 19:54:26 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 8FBF23A41A0
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 19:52:27 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 05475-10
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 18:52:24 +0000 (GMT)
Received: from davinci.ethosmedia.com (server226.ethosmedia.com [209.128.84.226])
by svr1.postgresql.org (Postfix) with ESMTP id E7C333A4182
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 19:52:24 +0100 (BST)
Received: from [64.81.245.111] (account josh@agliodbs.com HELO temoku.sf.agliodbs.com)
by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8)
with ESMTP id 6553982; Mon, 25 Oct 2004 11:53:49 -0700
From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Date: Mon, 25 Oct 2004 11:54:33 -0700
User-Agent: KMail/1.6.2
cc: Dennis Bjorklund <db@zigo.dhs.org>, Tom Lane <tgl@sss.pgh.pa.us>
References: <Pine.LNX.4.44.0410252019320.2015-100000@zigo.dhs.org>
In-Reply-To: <Pine.LNX.4.44.0410252019320.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-ID: <200410251154.33532.josh@agliodbs.com>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis,
> It doesn't discuss it. According to the spec a timestamp with time zone is
> a UTC value + a HH:MM offset from GMT. And intervals in the spec is either
> a year-month value or a day-time value. One can only compare year-month
> values with each other and day-time values with each other. So they avoid
> the problem of the how many days is a month by not allowing it.
That's not what Tom and I were talking about. The issue is that the spec
defines Days/Weeks as being an agglomeration of hours and not an atomic
entity like Months/Years are. This leads to some wierd and
calendar-breaking behavior when combined with DST, for example:
template1=> select '2004-10-09 10:00 PDT'::TIMESTAMPTZ + '45 days'::INTERVAL
template1-> ;
?column?
------------------------
2004-11-23 09:00:00-08
(1 row)
Because of the DST shift, you get an hour shift which is most decidely not
anything real human beings would expect from a calendar. The answer is to
try-partition INTERVAL values, as:
Hour/Minute/Second/ms
Day/Week
Month/Year
However, this could be considered to break the spec; certainly Thomas thought
it did. My defense is that the SQL committee made some mistakes, and
interval is a big one.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
From pgsql-hackers-owner+M60339=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:07:28 2004
Return-path: <pgsql-hackers-owner+M60339=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJ7Qf17120
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:07:27 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 666B73A41B0
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:07:23 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 13808-02 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:07:21 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 207F03A41AE
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:07:23 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id D243F3A4182
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:04:23 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 12122-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:04:18 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 52FFB3A3CF2
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:04:18 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9PJ4GUm022503;
Mon, 25 Oct 2004 15:04:16 -0400 (EDT)
To: josh@agliodbs.com
cc: pgsql-hackers@postgresql.org, Dennis Bjorklund <db@zigo.dhs.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251154.33532.josh@agliodbs.com>
References: <Pine.LNX.4.44.0410252019320.2015-100000@zigo.dhs.org> <200410251154.33532.josh@agliodbs.com>
Comments: In-reply-to Josh Berkus <josh@agliodbs.com>
message dated "Mon, 25 Oct 2004 11:54:33 -0700"
Date: Mon, 25 Oct 2004 15:04:16 -0400
Message-ID: <22502.1098731056@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Josh Berkus <josh@agliodbs.com> writes:
>> It doesn't discuss it. According to the spec a timestamp with time zone is
>> a UTC value + a HH:MM offset from GMT. And intervals in the spec is either
>> a year-month value or a day-time value. One can only compare year-month
>> values with each other and day-time values with each other. So they avoid
>> the problem of the how many days is a month by not allowing it.
> That's not what Tom and I were talking about. The issue is that the spec
> defines Days/Weeks as being an agglomeration of hours and not an atomic
> entity like Months/Years are.
I think though that these points are closely related. The reason the
spec does that is exactly that they are ignoring DST and so they can
assume that 1 day == 24 hours == 86400 seconds. In a DST-aware world
you have to make a separation between days and the smaller units, just
as months are separated from smaller units because there's not a fixed
conversion factor.
To some extent the interval and timestamptz issues are orthogonal, but
I think it would be good to fix them in the same release if possible.
There will undoubtedly be some backwards-compatibility problems, and
I suppose that users would prefer to take them all at once than via
the chinese water torture method ...
> However, this could be considered to break the spec; certainly Thomas
> thought it did. My defense is that the SQL committee made some
> mistakes, and interval is a big one.
I'm not clear to what extent we have to actually break the spec, as
opposed to extend it, in order to do this to the "interval" type. To do
everything the spec says we need to do, we'll have to be able to make
some comparisons that aren't strictly valid (which amounts to assuming
that 1 day == 24 hours for some limited purposes) but we already do much
the same things with respect to months. (See other thread about whether
1 year == 360 days...)
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
From pgsql-hackers-owner+M60340=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:12:25 2004
Return-path: <pgsql-hackers-owner+M60340=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJCNf17962
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:12:24 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id AA6B73A41C2
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:12:20 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 13059-08 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:12:19 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 50BAF3A41C1
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:12:20 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 2035E3A41B9
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:11:08 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 13808-08
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:11:04 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 5D4C03A41B2
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:11:04 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 156808467; Mon, 25 Oct 2004 21:11:04 +0200 (CEST)
Date: Mon, 25 Oct 2004 21:11:04 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251154.33532.josh@agliodbs.com>
Message-ID: <Pine.LNX.4.44.0410252103340.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Josh Berkus wrote:
> Dennis,
>
> > It doesn't discuss it. According to the spec a timestamp with time zone is
> > a UTC value + a HH:MM offset from GMT. And intervals in the spec is either
> > a year-month value or a day-time value. One can only compare year-month
> > values with each other and day-time values with each other. So they avoid
> > the problem of the how many days is a month by not allowing it.
>
> That's not what Tom and I were talking about.
You wanted to know what the standard said, and I told what I knew.
> The issue is that the spec defines Days/Weeks as being an agglomeration
> of hours and not an atomic entity like Months/Years are.
I don't know what you mean with this. The standard does treat them as
year
month
day
hour
minute
second (with fractions)
There is no weeks there, if that is what you mean.
> This leads to some wierd and calendar-breaking behavior when combined
> with DST, for example:
>
> template1=> select '2004-10-09 10:00 PDT'::TIMESTAMPTZ + '45 days'::INTERVAL
> template1-> ;
> ?column?
> ------------------------
> 2004-11-23 09:00:00-08
> (1 row)
>
> Because of the DST shift, you get an hour shift which is most decidely not
> anything real human beings would expect from a calendar.
I don't see how the above can be caused by the representation of an
interval. The above timestamp is
2004-10-09 10:00 PDT
which in the standard would be
2004-10-09 10:00 -07
and after the additon would be
2004-11-23 10:00:00-07
Here the time zone is wrong since the standard does not know about named
zones and dst.
An implementation like the one Tom (and I) want would start with
2004-10-09 10:00 PDT
and then after the addition one would get
2004-11-23 10:00:00 PST
At least that's my understanding of what we want and what we can get (plus
that we also need to support HH:MM tz values since those also exist in the
world, check this emails header for example).
It's possible that you discuss something else, but that has been lost on
me so far.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60341=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:15:18 2004
Return-path: <pgsql-hackers-owner+M60341=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJFHf18332
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:15:17 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id D2DE53A41BD
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:15:13 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 16799-02 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:15:12 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 928BF3A41A6
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:15:13 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 2AE4F3A41C4
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:13:02 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 15871-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:12:59 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 6881F3A41BC
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:12:59 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 09CC48467; Mon, 25 Oct 2004 21:12:59 +0200 (CEST)
Date: Mon, 25 Oct 2004 21:12:59 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251154.33532.josh@agliodbs.com>
Message-ID: <Pine.LNX.4.44.0410252112090.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Josh Berkus wrote:
> Hour/Minute/Second/ms
> Day/Week
> Month/Year
And just when I pressed "send" on the previous mail I got the problem
:-)
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 2: you can get off all lists at once with the unregister command
(send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
From pgsql-hackers-owner+M60342=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:20:32 2004
Return-path: <pgsql-hackers-owner+M60342=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJKVf19055
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:20:32 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 0D6103A418E
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:20:28 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 17860-02 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:20:26 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id AA4353A41B2
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:20:27 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 131A23A41BB
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:19:02 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 16799-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:18:51 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id BBD663A3B06
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:18:52 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 36B248467; Mon, 25 Oct 2004 21:18:52 +0200 (CEST)
Date: Mon, 25 Oct 2004 21:18:52 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251154.33532.josh@agliodbs.com>
Message-ID: <Pine.LNX.4.44.0410252114250.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Josh Berkus wrote:
> Hour/Minute/Second/ms
> Day/Week
> Month/Year
This is embarrasing. I'm still a bit confused :-)
The standard treat days as a separate entry, it does not assume that a day
is 24 hours. It restricts the hour field to the interval 0-23 so one can
never have something like 25 hours. So it does not need to worry about how
many days that translate to.
And why do we need weeks also?
Well, this is the last mail I send before I've been thinking about this
for a while more :-)
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 6: Have you searched our list archives?
http://archives.postgresql.org
From pgsql-hackers-owner+M60344=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:36:30 2004
Return-path: <pgsql-hackers-owner+M60344=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJaTf21902
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:36:29 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id E2F703A3CF2
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:36:25 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 23154-01 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:36:24 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 7935E3A3AC2
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:36:25 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 13AB03A41BC
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:35:09 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 21223-08
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:35:05 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id EA1E73A41B3
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:35:06 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9PJZ429022817;
Mon, 25 Oct 2004 15:35:04 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Josh Berkus <josh@agliodbs.com>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410252114250.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410252114250.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Mon, 25 Oct 2004 21:18:52 +0200"
Date: Mon, 25 Oct 2004 15:35:04 -0400
Message-ID: <22816.1098732904@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> The standard treat days as a separate entry, it does not assume that a day
> is 24 hours.
SQL92 says
4.5.2 Intervals
There are two classes of intervals. One class, called year-month
intervals, has an express or implied datetime precision that in-
cludes no fields other than YEAR and MONTH, though not both are
required. The other class, called day-time intervals, has an ex-
press or implied interval precision that can include any fields
other than YEAR or MONTH.
AFAICS the reason for this rule is that they expect all Y/M intervals to
be comparable (which they are) and they also expect all D/H/M/S intervals
to be comparable, which you can only do by assuming that 1 D == 24 H.
It seems to me though that we can store days separately and do interval
comparisons with the assumption 1 D == 24 H, and be perfectly
SQL-compatible as far as that goes, and still make good use of the
separate day info when adding to a timestamptz that has a DST-aware
timezone. In a non-DST-aware timezone the addition will act the same as
if we weren't distinguishing days from h/m/s. Therefore, an application
using only the spec-defined features (ie, only fixed-numeric-offset
timezones) will see no deviation from the spec behavior.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
From pgsql-hackers-owner+M60343=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 15:31:38 2004
Return-path: <pgsql-hackers-owner+M60343=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PJVZf21237
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 15:31:36 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 139FF3A41C0
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:31:32 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 21073-05 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 19:31:30 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 9E1723A41B8
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 20:31:31 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id C7A9E3A41A0
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 20:30:15 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 19517-04
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 19:30:05 +0000 (GMT)
Received: from wolff.to (wolff.to [66.93.249.74])
by svr1.postgresql.org (Postfix) with SMTP id 9A0483A4182
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 20:30:05 +0100 (BST)
Received: (qmail 26726 invoked by uid 500); 25 Oct 2004 19:40:57 -0000
Date: Mon, 25 Oct 2004 14:40:57 -0500
From: Bruno Wolff III <bruno@wolff.to>
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Josh Berkus <josh@agliodbs.com>, pgsql-hackers@postgresql.org,
Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Message-ID: <20041025194057.GA26356@wolff.to>
Mail-Followup-To: Dennis Bjorklund <db@zigo.dhs.org>,
Josh Berkus <josh@agliodbs.com>, pgsql-hackers@postgresql.org,
Tom Lane <tgl@sss.pgh.pa.us>
References: <200410251154.33532.josh@agliodbs.com> <Pine.LNX.4.44.0410252114250.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Pine.LNX.4.44.0410252114250.2015-100000@zigo.dhs.org>
User-Agent: Mutt/1.5.6i
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, Oct 25, 2004 at 21:18:52 +0200,
Dennis Bjorklund <db@zigo.dhs.org> wrote:
> On Mon, 25 Oct 2004, Josh Berkus wrote:
>
> > Hour/Minute/Second/ms
> > Day/Week
> > Month/Year
>
> This is embarrasing. I'm still a bit confused :-)
>
> The standard treat days as a separate entry, it does not assume that a day
> is 24 hours. It restricts the hour field to the interval 0-23 so one can
> never have something like 25 hours. So it does not need to worry about how
> many days that translate to.
>
> And why do we need weeks also?
For convenience. Just like years are a group of months, weeks are a group
of days.
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
From pgsql-hackers-owner+M60346=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 16:10:09 2004
Return-path: <pgsql-hackers-owner+M60346=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PKA8f26656
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 16:10:08 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 07A343A4201
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:10:05 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 62669-07 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 20:10:03 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id ACA1C3A4200
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:10:04 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 251663A41FE
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 21:08:18 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 62513-04
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 20:08:15 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id 3C94D3A3AC2
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 21:08:14 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 025568467; Mon, 25 Oct 2004 22:08:14 +0200 (CEST)
Date: Mon, 25 Oct 2004 22:08:14 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: Josh Berkus <josh@agliodbs.com>, <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <22816.1098732904@sss.pgh.pa.us>
Message-ID: <Pine.LNX.4.44.0410252204070.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Tom Lane wrote:
> There are two classes of intervals. One class, called year-month
> intervals, has an express or implied datetime precision that in-
> cludes no fields other than YEAR and MONTH, though not both are
> required. The other class, called day-time intervals, has an ex-
> press or implied interval precision that can include any fields
> other than YEAR or MONTH.
>
> AFAICS the reason for this rule is that they expect all Y/M intervals to
> be comparable (which they are) and they also expect all D/H/M/S intervals
> to be comparable, which you can only do by assuming that 1 D == 24 H.
I said I was not going to send any more mails, but here we go again :-)
The standard restrict the hour field to the interval 0-23, so there can
never be any compare between for example '1 day 1 hour' and '25 hours'.
This means that one can not add two intervals together to get a bigger
one but that it would still work to do timestamp+interval+interval.
> It seems to me though that we can store days separately and do interval
> comparisons with the assumption 1 D == 24 H, and be perfectly
> SQL-compatible as far as that goes, and still make good use of the
> separate day info when adding to a timestamptz that has a DST-aware
> timezone. In a non-DST-aware timezone the addition will act the same as
> if we weren't distinguishing days from h/m/s. Therefore, an application
> using only the spec-defined features (ie, only fixed-numeric-offset
> timezones) will see no deviation from the spec behavior.
I agree with this.
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
From pgsql-hackers-owner+M60347=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 16:20:45 2004
Return-path: <pgsql-hackers-owner+M60347=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PKKif28309
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 16:20:44 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 65B453A4215
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:20:40 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 66092-07 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 20:20:38 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 1DCD53A4210
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:20:40 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 803933A3AC2
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 21:18:00 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 64513-06
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 20:17:49 +0000 (GMT)
Received: from davinci.ethosmedia.com (server226.ethosmedia.com [209.128.84.226])
by svr1.postgresql.org (Postfix) with ESMTP id 726633A3CF2
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 21:17:51 +0100 (BST)
Received: from [64.81.245.111] (account josh@agliodbs.com HELO temoku.sf.agliodbs.com)
by davinci.ethosmedia.com (CommuniGate Pro SMTP 4.1.8)
with ESMTP id 6554308; Mon, 25 Oct 2004 13:19:17 -0700
From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
Date: Mon, 25 Oct 2004 13:20:01 -0700
User-Agent: KMail/1.6.2
cc: Dennis Bjorklund <db@zigo.dhs.org>, Tom Lane <tgl@sss.pgh.pa.us>
References: <Pine.LNX.4.44.0410252103340.2015-100000@zigo.dhs.org>
In-Reply-To: <Pine.LNX.4.44.0410252103340.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Disposition: inline
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Message-ID: <200410251320.01311.josh@agliodbs.com>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis,
> An implementation like the one Tom (and I) want would start with
>
> 2004-10-09 10:00 PDT
>
> and then after the addition one would get
>
> 2004-11-23 10:00:00 PST
Sounds like we're on the same page then.
> The standard restrict the hour field to the interval 0-23, so there can
> never be any compare between for example '1 day 1 hour' and '25 hours'.
> This means that one can not add two intervals together to get a bigger
> one but that it would still work to do timestamp+interval+interval.
Hour field of the timestamp, or hour field of interval? There a world of
difference.
As long as we're willing to live with the understanding that +1day 1 hour may
produce a slightly different result than + 25 hours, I don't see the problem.
Currently I can add +900 hours if I like, postgreSQL will support it.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60348=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 16:24:27 2004
Return-path: <pgsql-hackers-owner+M60348=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PKOQf28960
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 16:24:26 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 2AD843A419B
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:24:22 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 68942-02 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 20:24:20 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id E08EE3A4182
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:24:21 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id C8C413A419B
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 21:22:31 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 68322-02
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 20:22:28 +0000 (GMT)
Received: from zigo.dhs.org (as2-4-3.an.g.bonet.se [194.236.34.191])
by svr1.postgresql.org (Postfix) with ESMTP id BB2F53A41EC
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 21:22:29 +0100 (BST)
Received: from zigo.zigo.dhs.org (zigo.zigo.dhs.org [192.168.0.1])
by zigo.dhs.org (Postfix) with ESMTP
id 2B7368467; Mon, 25 Oct 2004 22:22:29 +0200 (CEST)
Date: Mon, 25 Oct 2004 22:22:29 +0200 (CEST)
From: Dennis Bjorklund <db@zigo.dhs.org>
To: Josh Berkus <josh@agliodbs.com>
cc: pgsql-hackers@postgresql.org, Tom Lane <tgl@sss.pgh.pa.us>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251320.01311.josh@agliodbs.com>
Message-ID: <Pine.LNX.4.44.0410252221150.2015-100000@zigo.dhs.org>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
On Mon, 25 Oct 2004, Josh Berkus wrote:
> > The standard restrict the hour field to the interval 0-23, so there can
> > never be any compare between for example '1 day 1 hour' and '25 hours'.
> > This means that one can not add two intervals together to get a bigger
> > one but that it would still work to do timestamp+interval+interval.
>
> Hour field of the timestamp, or hour field of interval? There a world of
> difference.
Hour field of an interval can be 0-23 according to the spec (doesn't say
that we need that restriction, but we do need to understand what the spec
say).
--
/Dennis Bj<42>rklund
---------------------------(end of broadcast)---------------------------
TIP 3: if posting/reading through Usenet, please send an appropriate
subscribe-nomail command to majordomo@postgresql.org so that your
message can get through to the mailing list cleanly
From pgsql-hackers-owner+M60349=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 16:34:48 2004
Return-path: <pgsql-hackers-owner+M60349=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9PKYlf00828
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 16:34:47 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id D7AD63A3BF2
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:34:43 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 72374-02 for <pgman@candle.pha.pa.us>;
Mon, 25 Oct 2004 20:34:41 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 99E183A3B88
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:34:43 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 534763A3C84
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Mon, 25 Oct 2004 21:32:42 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 71412-04
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Mon, 25 Oct 2004 20:32:36 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 798CA3A3B88
for <pgsql-hackers@postgresql.org>; Mon, 25 Oct 2004 21:32:38 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9PKWbDK023330;
Mon, 25 Oct 2004 16:32:37 -0400 (EDT)
To: josh@agliodbs.com
cc: pgsql-hackers@postgresql.org, Dennis Bjorklund <db@zigo.dhs.org>
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <200410251320.01311.josh@agliodbs.com>
References: <Pine.LNX.4.44.0410252103340.2015-100000@zigo.dhs.org> <200410251320.01311.josh@agliodbs.com>
Comments: In-reply-to Josh Berkus <josh@agliodbs.com>
message dated "Mon, 25 Oct 2004 13:20:01 -0700"
Date: Mon, 25 Oct 2004 16:32:37 -0400
Message-ID: <23329.1098736357@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Josh Berkus <josh@agliodbs.com> writes:
> As long as we're willing to live with the understanding that +1day 1 hour may
> produce a slightly different result than + 25 hours, I don't see the problem.
Right, which is exactly why we can't accept the spec's restriction that
the hour field be limited to 0-23. People may legitimately want to add
48 hours to a timestamp, and *not* have that mean the same as adding
"2 days". Besides, we would have a backwards-compatibility problem if
we tried to forbid it, since as you note we've always accepted such input.
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?
http://www.postgresql.org/docs/faqs/FAQ.html
From pgsql-hackers-owner+M60371=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 21:26:49 2004
Return-path: <pgsql-hackers-owner+M60371=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9Q1Qmf13334
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:26:49 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id A8E2F3A42A1
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:26:43 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 52441-04 for <pgman@candle.pha.pa.us>;
Tue, 26 Oct 2004 01:26:39 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 5F7503A42A0
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:26:43 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 02D5D3A427F
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Tue, 26 Oct 2004 02:25:27 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 52284-03
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Tue, 26 Oct 2004 01:25:22 +0000 (GMT)
Received: from houston.familyhealth.com.au (houston.au.fhnetwork.com [203.22.197.21])
by svr1.postgresql.org (Postfix) with ESMTP id 5C0723A42A0
for <pgsql-hackers@postgresql.org>; Tue, 26 Oct 2004 02:25:25 +0100 (BST)
Received: from houston.familyhealth.com.au (localhost [127.0.0.1])
by houston.familyhealth.com.au (Postfix) with ESMTP id 1BDCB2506C;
Tue, 26 Oct 2004 09:25:25 +0800 (WST)
Received: from [192.168.0.40] (work-40.internal [192.168.0.40])
by houston.familyhealth.com.au (Postfix) with ESMTP id 14E452506B;
Tue, 26 Oct 2004 09:25:25 +0800 (WST)
Message-ID: <417DA785.7010208@familyhealth.com.au>
Date: Tue, 26 Oct 2004 09:25:25 +0800
From: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
User-Agent: Mozilla Thunderbird 0.8 (Windows/20040913)
X-Accept-Language: en-us, en
MIME-Version: 1.0
To: Tom Lane <tgl@sss.pgh.pa.us>
cc: josh@agliodbs.com, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
References: <20041022184636.62D39EAEE02@svr1.postgresql.org> <200410250942.38212.josh@agliodbs.com> <21834.1098726893@sss.pgh.pa.us> <200410251108.52164.josh@agliodbs.com> <22093.1098728380@sss.pgh.pa.us>
In-Reply-To: <22093.1098728380@sss.pgh.pa.us>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
>>>regression=# set timezone to 'US/Arizona';
>>>SET
>>>regression=# select now();
>>>now
>>>-------------------------------
>>>2004-10-25 10:52:49.441559-07
>
>
>>Wow! When did that get fixed? How do I keep track of this stuff if you
>>guys keep fixing it? ;-)
That's worked for ages. What doesn't work is this:
usatest=# select current_timestamp at time zone 'US/Arizona';
ERROR: time zone "us/arizona" not recognized
Chris
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
From pgsql-hackers-owner+M60372=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 21:41:27 2004
Return-path: <pgsql-hackers-owner+M60372=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9Q1fPf15148
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:41:26 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id A941F3A4278
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:41:20 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 54196-09 for <pgman@candle.pha.pa.us>;
Tue, 26 Oct 2004 01:41:16 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id 50EEA3A4255
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:41:20 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 34AC13A4288
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Tue, 26 Oct 2004 02:39:55 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 54779-07
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Tue, 26 Oct 2004 01:39:42 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 3E9493A1D91
for <pgsql-hackers@postgresql.org>; Tue, 26 Oct 2004 02:39:45 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9Q1ditA003223;
Mon, 25 Oct 2004 21:39:46 -0400 (EDT)
To: Dennis Bjorklund <db@zigo.dhs.org>
cc: Robert Treat <xzilla@users.sourceforge.net>, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <Pine.LNX.4.44.0410230802200.2015-100000@zigo.dhs.org>
References: <Pine.LNX.4.44.0410230802200.2015-100000@zigo.dhs.org>
Comments: In-reply-to Dennis Bjorklund <db@zigo.dhs.org>
message dated "Sat, 23 Oct 2004 08:09:05 +0200"
Date: Mon, 25 Oct 2004 21:39:43 -0400
Message-ID: <3222.1098754783@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Dennis Bjorklund <db@zigo.dhs.org> writes:
> So if I understand you correctly you are planning to extend the current
> timestamp type to work with both named time zones and HH:MM ones? I didn't
> think you wanted the last one since your plan was to store a UTC+OID where
> the OID pointed to a named time zone. And I guess that you don't plan to
> add 00:00, 00:01, 00:02, ... as named zones with an OID.
I missed getting back to you on this, but I think we can do both. Some
random points:
* Once we expand timestamptz to bigger than 8 bytes, there's essentially
zero cost to making it 12 bytes, and for that matter we could go to 16
without much penalty, because of alignment considerations. So there's
plenty of space.
* What we need is to be able to represent either a fixed offset from UTC
or a reference of some kind to a zic database entry. The most
bit-splurging way of doing the former is a signed offset in seconds from
Greenwich, which would take 17 bits. It'd be good enough to represent
the offset in minutes, which needs only 11 bits.
* I suggested OIDs for referencing zic entries, but we don't have to do
that; any old mapping table will do. 16 bits would surely be plenty to
assign a unique label to every present and future zic entry.
* My inclination therefore is to extend timestamptz with two 16-bit
fields, one being the offset from UTC (in minutes) and one being the
zic identifier. If the identifier is zero then it's a straight numeric
offset from UTC and the offset field is all you need (this is the SQL
spec compatible case). If the identifier is not zero then it gives you
an index to look up the timezone rules. However, there is no need for
the offset field to go to waste; we should store the offset anyway,
since that might save a trip to the zic database in some cases.
* It's not clear to me yet whether the stored offset in the second case
should be the zone's standard UTC offset (thus always the same for a
given zone ID) or the current-time offset for the timestamp (thus
different if the timestamp is in daylight-savings or standard time).
* If we store the current-time offset then it almost doesn't matter
whether the timestamp itself is stored as a UTC or local time value;
you can trivially translate either to the other by adding or subtracting
the offset (*60). But I'm inclined to store UTC for consistency with
past practice, and because it will make comparisons a bit faster: you
can compare the timestamps without adjusting first. Generally I think
comparisons ought to be the best-optimized operations in a Postgres
datatype, because index operations will do a ton of 'em. (We definitely
do NOT want to have to visit the zic database in order to compare two
timestamptz values.)
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 4: Don't 'kill -9' the postmaster
From pgsql-hackers-owner+M60373=pgman=candle.pha.pa.us@postgresql.org Mon Oct 25 21:53:52 2004
Return-path: <pgsql-hackers-owner+M60373=pgman=candle.pha.pa.us@postgresql.org>
Received: from svr1.postgresql.org (svr1.postgresql.org [200.46.204.71])
by candle.pha.pa.us (8.11.6/8.11.6) with ESMTP id i9Q1rpf17038
for <pgman@candle.pha.pa.us>; Mon, 25 Oct 2004 21:53:51 -0400 (EDT)
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 1B6153A42AC
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:53:46 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 58642-09 for <pgman@candle.pha.pa.us>;
Tue, 26 Oct 2004 01:53:42 +0000 (GMT)
Received: from postgresql.org (svr1.postgresql.org [200.46.204.71])
by svr1.postgresql.org (Postfix) with ESMTP id CE6DE3A42A7
for <pgman@candle.pha.pa.us>; Tue, 26 Oct 2004 02:53:45 +0100 (BST)
X-Original-To: pgsql-hackers-postgresql.org@localhost.postgresql.org
Received: from localhost (unknown [200.46.204.144])
by svr1.postgresql.org (Postfix) with ESMTP id 768EE3A429E
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>; Tue, 26 Oct 2004 02:52:13 +0100 (BST)
Received: from svr1.postgresql.org ([200.46.204.71])
by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024)
with ESMTP id 58205-07
for <pgsql-hackers-postgresql.org@localhost.postgresql.org>;
Tue, 26 Oct 2004 01:52:07 +0000 (GMT)
Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130])
by svr1.postgresql.org (Postfix) with ESMTP id 397C43A4294
for <pgsql-hackers@postgresql.org>; Tue, 26 Oct 2004 02:52:11 +0100 (BST)
Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1])
by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id i9Q1q07B003307;
Mon, 25 Oct 2004 21:52:00 -0400 (EDT)
To: Christopher Kings-Lynne <chriskl@familyhealth.com.au>
cc: josh@agliodbs.com, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] timestamp with time zone a la sql99
In-Reply-To: <417DA785.7010208@familyhealth.com.au>
References: <20041022184636.62D39EAEE02@svr1.postgresql.org> <200410250942.38212.josh@agliodbs.com> <21834.1098726893@sss.pgh.pa.us> <200410251108.52164.josh@agliodbs.com> <22093.1098728380@sss.pgh.pa.us> <417DA785.7010208@familyhealth.com.au>
Comments: In-reply-to Christopher Kings-Lynne <chriskl@familyhealth.com.au>
message dated "Tue, 26 Oct 2004 09:25:25 +0800"
Date: Mon, 25 Oct 2004 21:52:00 -0400
Message-ID: <3306.1098755520@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
X-Virus-Scanned: by amavisd-new at hub.org
X-Mailing-List: pgsql-hackers
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org
X-Virus-Scanned: by amavisd-new at hub.org
Status: OR
Christopher Kings-Lynne <chriskl@familyhealth.com.au> writes:
> That's worked for ages. What doesn't work is this:
> usatest=# select current_timestamp at time zone 'US/Arizona';
> ERROR: time zone "us/arizona" not recognized
Right, and similarly you can do
regression=# select '2004-10-25 21:32:33.430222 MST'::timestamptz;
timestamptz
-------------------------------
2004-10-26 00:32:33.430222-04
(1 row)
but not
regression=# select '2004-10-25 21:32:33.430222 US/Arizona'::timestamptz;
ERROR: invalid input syntax for type timestamp with time zone: "2004-10-25 21:32:33.430222 US/Arizona"
I would like to see both of these cases working in 8.1; and furthermore
I'd like to see the timezone specs coming back as entered, not as bare
numeric offsets. (This will need to be adjustable via a DateStyle
option, of course, but I want the information to be in there whether it
is displayed or not.)
regards, tom lane
---------------------------(end of broadcast)---------------------------
TIP 7: don't forget to increase your free space map settings
Reference in New Issue View Git Blame Copy Permalink