Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
> If you try it using nextval(), you'll notice that the function does
> in fact get called twice per row, but one of the results is thrown
> away and replaced with the other one.
Yeah. The problem is that setrefs.c is generating a tlist for the
hashagg node in which both output expressions point to the first
output of the underlying scan node, because it's just relying on
equal() to match up the expressions. I'm testing a fix now ...
regards, tom lane