Re: TO_CHAR(timestamptz,datetimeformat) wrong after DST change

On 03/18/2011 07:59 AM, jonathansfl wrote:
> My TO_CHAR function is now an hour off thanks to Daylight Savings Time.
> The dates are correct (I'm in EST: TZ=-04) but my function now returns TIME
> an hour early.
> (prior to DST we were TZ=-05).
>
> TIMESTAMPTZ data (v_dt): 2011-03-17 18:21:50-04
> FUNCTION SNIPPET: to_char(v_dt, 'mm/dd/yyyy hh:mi AM')
> FUNCTION RETURNS: 03/18/2011 09:21 AM
> FUNCTION SHOULD RETURN: 03/18/2011 10:21 AM
>
> postgres=# show time zone;
>       TimeZone
> ------------------
>   America/New_York
> (1 row)
>

You are leaving out something critical. Based on what you've shown us,
you shouldn't get either answer, you should get "03/17/2011 06:21 PM".

select to_char(timestamptz '2011-03-17 18:21:50-04', 'mm/dd/yyyy hh:mi AM');

to_char
-----------
03/17/2011 06:21 PM

My money is on an accidental conversion between timestamp and
timestamptz in some part of the function you haven't shown us.

Cheers,
Steve