Re: GiST limits on contrib/cube with dimension > 100?

[Siarhei Siniak]

A uniform set of points with a dimension 128 and type cube. That has a size of 
50 ** 3. Can be queried for a nearest neighbor at a speed of 10 queries per 
second with limit varying from 1 to 25.
It works better than when no index used at all. So gist gives here a speed up.
The documentation of postgresql doesn't mention complexity of such an index. 
I've got confused as to its speed.
Does postgresql allow for an approximate nearest neighbor search?
 https://github.com/erikbern/ann-benchmarks has a lot of efficient 
implementations.