Re: Inserting / selecting rows with TIMESTAMP

Claire De Longchamp <cdl@abdmf.com> writes:
>                    Table "hre_gaz"
>  Column |              Type              | Modifiers
> --------+--------------------------------+-----------
>  poste  | smallint                       | not null
>  gaz    | smallint                       | not null
>  temps  | timestamp(0) without time zone | not null
>  valeur | integer                        |
>  qual   | integer                        |
>  type   | character(1)                   |
> Primary key: hre_gaz_pkey
> Triggers: RI_ConstraintTrigger_462203,
>           RI_ConstraintTrigger_462209

> RsqaDb=# insert into hre_gaz (poste,gaz,temps,valeur,qual,type)
> RsqaDb-# values (3,1,'1998-04-05 02:00:00'::timestamp,6,1,'S') ;
> ERROR:  Cannot insert a duplicate key into unique index hre_gaz_pkey

What PG version is this?

If it's 7.2, then I think you're getting burnt by the fact that
::timestamp means coercion to timestamp *with* time zone.  When that
value is then coerced to timestamp without time zone, you can get funny
behavior right around the times of daylight-savings transitions.
In particular, I don't think '1998-04-05 02:00:00' is actually a valid
time, at least under US DST rules --- it comes out as '03:00:00' for me.

Either leave off the explicit coercion, or coerce to "timestamp without
time zone", or update to 7.3 in which "timestamp" means "timestamp without
time zone".

            regards, tom lane