[postgis-devel] ST_Envelope & spatial index

[Andrea Peri]

Hi,

The raster function ST_Envelope() will use the GIST Index if existent ?

It seem to be particularly slow.

So I try to do this:

explain select ST_Extent(ST_Envelope(rast)) from raster.ofc10k_2010 limit 1;

And see that.

Limit  (cost=48027.93..48027.94 rows=1 width=32)
  ->  Aggregate  (cost=48027.93..48027.94 rows=1 width=32)
        ->  Seq Scan on ofc10k_2010  (cost=0.00..37419.53 rows=1414453
width=32)

Also I verify there the GIST Index create from raster2pgsql

CREATE INDEX ofc10k_2010_rast_gist
  ON raster.ofc10k_2010
  USING gist
  (st_convexhull(rast) );

-- 
-----------------
Andrea Peri
. . . . . . . . .
qwerty àèìòù
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