Alexander Korotkov <aekorotkov@gmail.com> writes:
> On Mon, Dec 15, 2014 at 4:12 PM, Heikki Linnakangas <hlinnakangas@vmware.com
>> wrote:
>> Right. I also looked at it briefly, but I wasn't sure if we really want
>> it. AFAICT, no-one has actually asked for that operator, it was written
>> only to be an example of an operator that would benefit from the knn-gist
>> with recheck patch.
> Lack of recheck is major limitation of KNN-GiST now. People are not asking
> for that because they don't know what is needed to implement exact KNN for
> PostGIS. Now they have to invent kluges like this:
> [ query using ORDER BY ST_Distance ]
It's not apparent to me that the proposed operator is a replacement for
ST_Distance. The underlying data in an example like this won't be either
points or polygons, it'll be PostGIS datatypes.
In short, I believe that PostGIS could use what you're talking about,
but I agree with Heikki's objection that nobody has asked for this
particular operator.
regards, tom lane