"Billow Gao" <billowgy@gmail.com> writes: > A very simple C function which I copied from the manual. > And I found that it's called twice. You do realize that it's *supposed* to be called twice? Once to return the first row, and again to say it's done returning rows. But the info messages you show are strange anyway. I tried your example here and got the results I'd expect: regression=# select * from retcomposite(1,48); INFO: 1 INFO: 2 INFO: 3 INFO: 4 INFO: 2 INFO: 5 f1 | f2 | f3 ----+----+----- 48 | 96 | 144 (1 row) I think the code you showed must not quite match what you're actually executing. Maybe you recompiled the code and forgot to do a LOAD or start a fresh session to bring in the new .so file? regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster