Обсуждение: Postgresql 7.0 bug

============================================================================
                        POSTGRESQL BUG REPORT TEMPLATE
============================================================================


Your name        : Eric Prevost-Dansereau
Your email address    : eric@esc.rosemere.qc.ca


System Configuration
---------------------
  Architecture (example: Intel Pentium)      : Intel Pentium II

  Operating System (example: Linux 2.0.26 ELF)     : Linux 2.2.13 ELF

  PostgreSQL version (example: PostgreSQL-6.5.1):  PostgreSQL-7.0

  Compiler used (example:  gcc 2.8.0)        : gcc 2.91.66


Please enter a FULL description of your problem:
------------------------------------------------

When I execute from psql:
    SELECT '2000-04-03'::timestamp - '2000-04-02'::timestamp;

I get:
     ?column?
    ----------
     23:00
    (1 row)

Why april 2nd, 2000 don't last 1 day (or 24 hours) ?






Please describe a way to repeat the problem.   Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------

SELECT '2000-04-03'::timestamp - '2000-04-02'::timestamp;




If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------

I don't have any idea

root <root@esc.rosemere.qc.ca> writes:
>     SELECT '2000-04-03'::timestamp - '2000-04-02'::timestamp;
>      ?column?
>     ----------
>      23:00
>     (1 row)

> Why april 2nd, 2000 don't last 1 day (or 24 hours) ?

Here in the USA, that is the right answer because 4/2 was a daylight
savings switchover date.  Notice the difference in timezones:

regression=# select '2000-04-03'::timestamp;
        ?column?
------------------------
 2000-04-03 00:00:00-04
(1 row)

regression=# select  '2000-04-02'::timestamp;
        ?column?
------------------------
 2000-04-02 00:00:00-05
(1 row)

If it wasn't a DST change date where you live, then you are running
with the wrong timezone setting...

            regards, tom lane

root wrote:
>
> When I execute from psql:
>         SELECT '2000-04-03'::timestamp - '2000-04-02'::timestamp;
>
> I get:
>          ?column?
>         ----------
>          23:00
>         (1 row)
>
> Why april 2nd, 2000 don't last 1 day (or 24 hours) ?

Because April 2nd was the beginning of daylight savings time.

Karl DeBisschop
www.infoplease.com