On Sat, Aug 20, 2011 at 2:58 PM, Stephen Woodbridge <[email protected]> wrote: > On 8/20/2011 3:34 PM, Jaime Casanova wrote: >> >> On Sat, Aug 20, 2011 at 7:36 AM, Charles Galpin<[email protected]> wrote: >>> >>> I assume you mean it takes a long time? The key is to create a buffer >>> around the point that is as big as you feel necessary to make a >>> match, and then in your where clause only match lines that intersect >>> this. That way the index is used to limit the number of >>> candidates to get the distance for. Something like >>> >>> where line&& st_expand(myPoint, bufferSizeInYourProjectionUnits) >>> >> >> st_dwithin() doesn't do this automatically? >> but i should admit it wasn't useful for me... it still require a seq >> scan on the whole table >> > > Have you create a gist (not a btree) index on your geometry column? >
Yes, I have... Here was posted my problem (http://postgis.refractions.net/pipermail/postgis-users/2011-August/030559.html) and this is the EXPLAIN ANALYZE using st_dwithin() in the query (http://explain.depesz.com/s/rbX) the table has a GiST index on the table transmitter_mv -- Jaime Casanova www.2ndQuadrant.com Professional PostgreSQL: Soporte 24x7 y capacitación _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
