[postgis-users] optimize query

[Pierre Racine]

Is your raster tiled? How?

Is it indexed?

Does your query actually use the index?

It is maybe not a good idea to get the srid for ST_Intersects from the raster. Try to hardcode it to see if it makes a difference.

Pierre

> -----Original Message-----
> From: postgis-users-bounces at postgis.refractions.net [mailto:postgis-users-
> bounces at postgis.refractions.net] On Behalf Of Gold, Jack L (US SSA)
> Sent: Tuesday, May 22, 2012 5:17 PM
> To: PostGIS Users Discussion (postgis-users at postgis.refractions.net)
> Subject: [postgis-users] optimize query
> 
> I'm finding a search query we wrote is running really slow.  Any ideas on how to
> optimize this better?  Or is this the best I can do?
> 
> 
> 
> SELECT ST_Value(rast, ST_Transform(ST_SetSRID(ST_Point(66.12, 37.32),
> 4326),ST_SRID(rast))) FROM dted_elevations WHERE ST_Intersects(rast,
> ST_Transform(ST_SetSRID(ST_Point(66.12, 37.32), 4326), ST_SRID(rast)));
> 
> 
> 
> --Jack Gold
> 
> 
> 
>