Andrew Dunstan <andrew@dunslane.net> writes:
> First reaction is that it would mean we could never pass them by
> reference. I know PLPerl uses in effect pass by copy, but what does
> PLPgsql do?
It's not really an issue, because plpgsql keeps track of whether
the current value of the variable "belongs" to it or not. Look
at the "freeval" manipulations in pl_exec.c.
regards, tom lane