Re: wip: functions median and percentile

Greg Stark <gsstark@mit.edu> writes:
> On Thu, Aug 19, 2010 at 11:59 AM, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>> I am sending a prototype implementation of functions median and
>> percentile. This implementation is very simple and I moved it to
>> contrib for this moment - it is more easy maintainable. Later I'll
>> move it to core.

> So if the entire result set fits in memory it would be nice to use the
> O(n) Quickselect algorithm -- which would only be a small change to
> the existing Quicksort code -- instead of sorting the entire set.

That seems like rather a lot of added infrastructure for functions whose
popularity is at best unknown.  I think we should KISS for the first
implementation.
        regards, tom lane