[ bugs list removed, hackers added.]
Tom Lane wrote:
> Bruce Momjian <[email protected]> writes:
> > I saw a lot of disussion because I forgot to specify that my tests were
> > for EST5EDT, but what about the use of interval_justify_hours() in
> > timestamp_mi(). Is this something we want to change?
>
> It's too late to mess with it for 8.1, but see my previous message
> proposing a set of TODO items for future work.
Yes, it is late, but I am worried about adding an interface change that
we will later revert in 8.2. In 8.0.X I see the query returning the '25
hour' answer:
SELECT
('2005-10-29 13:22:00-04'::timestamptz +
('2005-10-30 13:22:00-05'::timestamptz -
'2005-10-29 13:22:00-04'::timestamptz)) at time zone 'EST';
timezone
---------------------
2005-10-30 13:22:00
(1 row)
In current CVS the top query returns '14:22:00'. Do we change this for
8.1, then change it back in 8.2? That seems bad to me.
Actually, 8.0.X returns '1 day, 1 hour' for the subtraction, which we
treat in 8.0.X as '25 hours':
SELECT
('2005-10-30 13:22:00-05'::timestamptz -
'2005-10-29 13:22:00-04'::timestamptz);
?column?
----------------
1 day 01:00:00
(1 row)
In 8.0.X, because we didn't have a 'days' field, we could treat '1 day 1
hour' as always '25 hours', and could display the results as days/hours.
If we remove interval_justify_hours(), then we are always going to
display timestamp subtraction in hours (not days), e.g. '6422 hours'
(yea, ugly) unless they manually call interval_justify_hours().
Keep in mind that the addition of the interval_justify_hours() did
generate some regression test changes, so removing
interval_justify_hours() might just take the results back to what we had
in 8.0. My point is that regression changes caused by its removal might
not be a good guide to determining compatibility with 8.0.X.
I guess my point is that we are changing 8.0.X behavior so we better be
sure it is now the way we want it to remain.
--
Bruce Momjian | http://candle.pha.pa.us
[email protected] | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
