Re: proposal: tuplestore, tuplesort aggregate functions

Pavel Stehule <pavel.stehule@gmail.com> writes:
> 2010/8/18 Tom Lane <tgl@sss.pgh.pa.us>:
>> There would be plenty of scope to re-use the machinery without any
>> SQL-level extensions.  All you need is a polymorphic aggregate
>> transition function that maintains a tuplestore or whatever.

> Have we to use a transisdent function? If we implement median as
> special variant of aggregate - because we need to push an sort, then
> we can skip a transident function function - and call directly final
> function.

Well, that would require a whole bunch of *other* mechanisms, which you
weren't saying anything about in your original proposal.  But driving
it off the transtype declaration would be quite inappropriate anyway IMO.
        regards, tom lane