Re: wip: functions median and percentile

On Thu, Aug 19, 2010 at 11:33 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 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.

+1.  I think the functions are useful, but the perfect is the enemy of the good.

--
Robert Haas
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