[postgis-users] Spatial intersect optimization

[Josh Livni]

I am fairly inexperienced with optimizing spatial queries in PostGIS, 
and am trying to do something similar to the example 4.6.2.4 in the 
documentation at http://postgis.refractions.net/docs/ch04.html

It notes that this will be slow due to summarizing.  I have over 500k 
parcels, and I'd like to do some summary stats in each of about 15k 
polygons.

My question is, could the example mentioned above become faster if it 
took better advantage of the gist indices?  or is it already?  How would 
I go about adding some kind of 'AND the_geom && (bbox of m.geom)' to the 
  WHERE clause?

Thanks for any hints,

   -Josh