Erwin Brandstetter <brsaweda@gmail.com> writes:
> Hi all!
> This may seem unimportant, but I still would like to know.
> I have columns for timestamps without fractional digits, so I could
> define them as timestamp(0).
> However, there is no way fractions could ever enter anyway, because
> triggers and / or checks guarantee values without fractional seconds.
> Is it advantageous to define the column as timestamp(0) or simply as
> timestamp?
> Does the query planner or any other part of the RDBMS profit from the
> additional information in the definition?
> Or do I just create an overhead of useless checks or conversions
> (however small)?
There's no advantage to the system from knowing that, but consider that
having timestamp_in force the values to be nonfractional is likely to be
faster than having logic in a trigger to do it.
regards, tom lane