Josh Berkus <josh@agliodbs.com> writes:
> On 9/21/11 1:56 PM, Tom Lane wrote:
>> A look in pg_operator will show you that these operators have no
>> associated selectivity estimators at all. It's not so much "broken"
>> as "unimplemented".
> Oh! I was assuming that the special case code kicked in regardless.
> So we implemented the rewrite to < and > for the actual execution, but
> not for cost estimates?
If you mean the indexscan optimization, we do know how to estimate the
cost of the indexscans, because that depends mostly on the behavior of
the added < or > condition(s). This does not imply knowing how to
estimate the behavior of >>= itself.
regards, tom lane