Spatially cluster PostGIS tables

If your query pattern evolves around getting geometries that are often spatially close together it might make sense to cluster the table on a spatial correlated field.

-- first create a functional index on the geohash of your geometry
create index idx_polygon_geohash on zone (st_geohash(polygon));

-- vacuum and analyze your db
vacuum analyze zone;

-- cluster the table on that newly created index
cluster zone using idx_cl_polygon_geohash;

performance gains heavily depend on the size of the response payload and the query pattern.

see: here