Greg Stark <stark@mit.edu> writes:
> Well in many cases stype will just be internal for many of them. That
> doesn't mean they're the same.
> Hm, I suppose it might if they have the same sfunc.
> This is actually where I started but we concluded that we needed some
> declaration that the aggregates were actually related and would interpret
> the state the same way and not just that it happened to use the same
> storage format.
Well, in practice you'd need to also compare the input datatype (consider
polymorphic aggregates) and initcond. But the sfunc isn't told which
finalfunc will be applied, so any aggregates that share the same sfunc and
have the other conditions the same *must* have the identical transition
data behavior. I don't see any reason to invent new syntax, and there
are good reasons not to if we don't have to.
regards, tom lane