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 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
