Postgis Gist Index

[Clint Johnson]

http://www.postgis.fr/book/print/186
Read section 4.5.2 Using Indexes for instructions on how to force GiST 
usage.

Also note that VACCUUM ANALYZE; by itself will not suffice for Postgres 
7.4; an additional command is required.


Clint


Bertsch wrote:
> Hi List,
>
> As I was reading in the PostGIS manual a GIST index on the geometry column
> will speed up the application in several cases.
> So i was creating an index on my south_america_large table with CREATE INDEX
> south_america_large_index ON south_america_large USING GIST(the_geom
> GIST_GEOMETRY_OPS); VACUUM ANALYZE;
> Code:
> layer->set("data","the_geom FROM (SELECT the_geom,gid FROM
> south_america_large) AS myquery USING UNIQUE GID USING SRID=-1");
> map->setExtent(-54,-20,-39,-9); the extension of this map is (-117,-56) -
> (-34,32)
>
> When i run the application i get the same time using the database with GIST
> or using it without GIST. Furthermore i was trying the same with a shape
> file and a quadtree index and i got better results for the shapefile with
> the quadtree index. Maybe someone can help me.
> Thanks,
> Clemens
> --
> View this message in context: http://www.nabble.com/Postgis-Gist-Index-t1469264.html#a3971891
> Sent from the Mapserver - User forum at Nabble.com.
>   


-- 
Clint Johnson
Refractions Research Inc.
Cjohnson at refractions.net