Simon Riggs <simon@2ndquadrant.com> writes:
> It might be worth teaching the optimiser that if it has an index on an
> immutable function that if we have WHERE x = k and a functional index on
> f(x) then we can access the functional index with
> f(x) = f(k), as long as we also reapply the original WHERE clause.
As I just pointed out to Gaetano, this is utterly wrong. We can't
assume that much about the behavior of equality.
regards, tom lane