Re: BUG #12739: to_timestamp function conver string to time incorrectly

lstrupinskaya(at)gmail(dot)com writes:
> When trying to use to_timestamp function to convert string '3/10/2013 2:30'
> to timestamp it was actually converted into 3/10/2013 3:30.

> Below is select statement:

> select to_timestamp('3/10/2013 2:30','MM/DD/YYYY HH24:MI');

If you're running with USA DST rules, there was no such thing as 2:30
observed local time on that date: clocks advanced from 1:59:59 to 3:00:00.

As documented, Postgres handles invalid or ambiguous times near a DST
transition by supposing that the given time is local standard time.
So in the New York zone for instance, 2:30 local standard time (GMT-5)
would equate to 3:30 local daylight time (GMT-4), and daylight time would
have been what was observed at that instant, so that's what gets printed.

If you don't want DST-aware handling of timestamps, don't use type
timestamptz nor to_timestamp (which actually produces timestamptz).

regards, tom lane