Dominique Devienne <ddevienne(at)gmail(dot)com> writes:
> Will the query planner be able to *peek* into the args, and turn the
> `colN like $N`
> into a no-op?
No. It would not do that even if the pattern were constant '%';
it doesn't know that much about that particular function.
There is a notion of "custom plans" in which parameter values are
inserted as constants, precisely to allow simplifications based on
known constant values. But this particular case isn't implemented.
I am entirely unfamiliar with the terminology "bind-peeking", so
I can't say whether that's effectively the same thing as our
custom plans.
regards, tom lane