[postgis-devel] ST_DistanceCached(geog, geog), ST_DWithinCached(geog, geog)

[Paul Ramsey]

I've temporarily committed two functions to Geography support in trunk,

ST_DistanceCached(geog, geog)
ST_DWithinCached(geog, geog, double)

These would take over from ST_Distance(geog, geog) and
ST_DWithin(geog, geog, double) when good behavior, performance are
confirmed. The only difference between them and their antecedants is
that they try and cache an internal geography tree. This seems to make
a massive, monster difference for distance calculations. Oddly, I
haven't been able to demonstrate a speed difference in DWithin yet, at
least not with fairly small tolerance values.

Please feel free to test and let me know how things go.

P.