On Fri, Jun 12, 2009 at 10:34:21AM +0100, Pedro Doria Meunier wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Thank you Nicklas for your advice! That actually accomplishes it with > a notable exception: > > Altough the table has a gist index on the geom column the query is > always executed in Seq Scan mode... > > I ask the gurus which fx is causing this, st_centroid or st_collect ?
It's the WHERE clause driving access strategy. If you're giving no conditions of course sequential scan is faster. Only reason to use the gist geometry index is if you use the && operator in the WHERE clause, and the analizer finds it to be enough selective to prefere index vs. sequential scan. --strk; Free GIS & Flash consultant/developer () ASCII Ribbon Campaign http://foo.keybit.net/~strk/services.html /\ Keep it simple! _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
