2010/8/18 Tom Lane <t...@sss.pgh.pa.us>: > Pavel Stehule <pavel.steh...@gmail.com> writes: >> 2010/8/18 Tom Lane <t...@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. >
I'll test both variant first. Maybe there are not any significant difference between them. Now nodeAgg can build, fill a tuplesort. So I think is natural use it. It needs only one - skip a calling a transident function and directly call final function with external tuplesort. Minimally you don't need 2x same code. Regards Pavel Stehule > regards, tom lane > -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
