Re: Timestamp confusion

"Rob Richardson" <Rob(dot)Richardson(at)rad-con(dot)com> writes:
> I have a table with a column declared to contain a timestamp with time
> zone. A database function inserts a row into this table using the
> following statement:

> insert into alarm_hold (charge, hold_code, hold_generated,
> condition_date) values (ChargeNum, '0471', 0, current_timestamp at time
> zone 'UTC');

> The resulting value contained in the timestamp field is 2010-09-28
> 13:09:27.015-04.

> Since I am in the Eastern time zone of the United States and daylight
> savings time is in effect, the -04 indicates that it is 4 hours earlier
> for me than it is in Greenwich, England. And this value was generated
> at 9:09 this morning local time, so the 13:09 is understandable.

> The thing I am confused about is why the "-04" is there.

You declared the column as timestamp with time zone. The AT construct
produced a timestamp without time zone, viz "2010-09-28 13:09:27.015",
which the system then had to convert to timestamp with time zone; which
it did using the assumption that local time was meant.

Basically, you don't want to use AT TIME ZONE here; it loses information
to no good purpose. Just insert the result of current_timestamp and
call it good.

regards, tom lane