Re: Index-only scans for multicolumn GIST - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Index-only scans for multicolumn GIST
Date
Msg-id 21665.1406037961@sss.pgh.pa.us
Whole thread Raw
In response to Re: Index-only scans for multicolumn GIST  (Heikki Linnakangas <hlinnakangas@vmware.com>)
Responses Re: Index-only scans for multicolumn GIST  (Emre Hasegeli <emre@hasegeli.com>)
List pgsql-hackers
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



pgsql-hackers by date:

Previous
From: Robert Haas
Date:
Subject: Re: Index-only scans for multicolumn GIST
Next
From: Andres Freund
Date:
Subject: Re: [bug fix] Suppress "autovacuum: found orphan temp table" message