Re: timestamp(0) vs. timestamp

On 27.04.2011 19:36, Tom Lane wrote:
> 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



Thank you for the insight.
Is there any kind of overhead for timestamp_in due to the precision modifier - if non-fractional values are given?


Regards
Erwin Brandstetter