KNN gist with recheck for 9.5?
|Reported by:||robe||Owned by:||pramsey|
I noticed this feature is on the commitfest 9.4 block for consideration.
Would be cool if we can push it along and leverage it in 2.2. As best I understand it, it would mean our KNN would act as a true distance check.
From patch thread
KNN-GiST provides ability to get ordered results from index, but this order is based only on index information. For instance, GiST index contains bounding rectangles for polygons, and we can't get exact distance to polygon from index (similar situation is in PostGIS). In attached patch, GiST distance method can set recheck flag (similar to consistent method). This flag means that distance method returned lower bound of distance and we should recheck it from heap.
Am I missing anything here?