Re: Index-only scans for multicolumn GIST

Heikki Linnakangas <hlinnakangas@vmware.com> writes:
> For a circle, the GiST index stores a bounding box of the circle. The 
> new fetch function reverses that, calculating the radius and center of 
> the circle from the bounding box.

> Those conversions lose some precision due to rounding. Are we okay with 
> that?

That seems like a nonstarter :-(.  Index-only scans don't have a license
to return approximations.  If we drop the behavior for circles, how much
functionality do we have left?
        regards, tom lane