Richard Huxton <dev@archonet.com> writes:
> Can I ask why, since the plan is constructed at query-time the parameters
> aren't substitued *before* planning?
Because then the plan couldn't be re-used. A SQL function may be
executed many times in a query, so the plan has to be reusable.
(Or, if you prefer, we have query-level caching of SQL function plans.)
regards, tom lane
