EXISTS(SELECT * FROM y WHERE y.a > 0)
If the first row of collection y fulfills the WHERE predicate, there's no reason to continue perusing the rest of the rows. Now, what if 'y' is a function returning SETOF something? I see only one possible way for a C-function to detect that it doesn't need to return more rows and that would be if the FuncCallContext call_cntr reaches max_calls.
My question is, what happens when the evaluator doesn't need more rows? Will it:
a) call the function with call_cntr >= max_calls?
b) continue calling until the set is exhausted anyway?
c) simply stop calling?
a) seems unlikely since max_calls is set by the user, b) doesn't seem very optimal, and c) would be very bad since it doesn't give me any chance to release the resources that where used in order to produce the rows.
Regards, Thomas Hallgren
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