Yl Zhou <andrew.ylzhou@gmail.com> writes:
> But I have to use 7.3 due to some limitations. Can I do it in 7.3?
Probably, but I forget how (and I can guarantee that it will break
when you do move to 8.0 or later, because we changed the internal
representation of rowtype arguments). You'd be *much* better off to
spend your time fixing whatever it is that's keeping you on 7.3.
regards, tom lane