2008/12/25 Greg Stark <greg.st...@enterprisedb.com>: > Yeah, it seems like adding a flag like iswindowable to aggregate functions > is the safest option. > > It would be nice if it represented an abstract property of the state > function or final function rather than just "works with the implementation > of window functions". I'm not sure what that property is though - > isidempotent? isreentrant? Maybe just a vague isrepeatable?
No, I meant wrinting such like: Datum some_trans_fn(PG_FUNCTION_ARGS) { if (fcinfo->context && IsA(fcinfo->context, WindowAggState)) elog(ERROR, "some_agg does not support window aggregate"); ... } rather than adding column to catalog. To add flag you must add new syntax for CREATE AGGREGATE, which is slightly more painful. Regards, -- Hitoshi Harada -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers