Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> The only disadvantage I see of just documenting this is that someone
> might write a user-defined index opclass that works like this, and
> they won't be able to use this until at least 9.1 (or at least, not
> without patching the source).
I don't actually think that anyone's very likely to write a <>-like index
operator. It's approximately useless to use an index for such a query.
Or, to put it differently: if nobody's done that in the past twenty
years, why is it likely to happen before 9.1?
regards, tom lane