Hello very nice! I tested it and works very well.
And I looking for implementation in core. Two notes: * should to support string_agg and array_agg Regards Pavel 2013/8/26 Vik Fearing <vik.fear...@dalibo.com> > On 08/26/2013 02:39 PM, Pavel Stehule wrote: > > Hello > > > > Three years ago we worked on implementation of median function. > > > > > http://www.postgresql.org/message-id/aanlktimrksuoggsk7-gtxnvjjgl-1qvuqxiduszqw...@mail.gmail.com > > > > > > Can we implement this function now? > > > > There are a few opened questions: > > > > * immutable parameters of aggregate functions > > > > * effective implementation when data are in memory > > > > * effective implementation when data are out of memory > > > > * effective implementation for usage as window function - running median. > > > > Better than before, we can choose between hashing and sorting based > > aggregation. But tuplesort implementation is not right for using as > > window function. Second issue can be a not possible reusing of > > tuplesort for more final functions - median, percentile in one query. > > > > Ideas how to solve this task? Can we move forward in some points? > > Take a look at the standard-compliant WITHIN GROUP that is currently in > development for 9.4. > > http://www.postgresql.org/message-id/2b8b55b8ba82f83ef4e6070b95fb0...@news-out.riddles.org.uk > > -- > Vik > >
