[postgis-devel] Issue 95 in postgis: PostGIS 1.4 documentation update

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Updates:
	Status: Testing

Comment #12 on issue 95 by ke... at refractions.net: PostGIS 1.4 documentation  
update
http://code.google.com/p/postgis/issues/detail?id=95

I updated the note on operators to reflect the fact the fact that they do  
indeed use
indexes.

However, the caution on the = operator is left as is.  For the life of me,  
I can't
engage the index using this operator no matter what kind of selectivity I  
try for a
large spatial table.

Mark, are you sure that every operator uses indexes? I don't think this one  
does.

CREATE TABLE foo AS
   SELECT st_makepoint(random(), random()) AS the_geom
   FROM generate_series(1, 100000);
CREATE INDEX foo_geom_idx ON foo using gist (the_geom);
ANALYZE foo;
EXPLAIN SELECT * FROM foo WHERE the_geom && 'POINT(0.5 0.5)';
                                      QUERY PLAN
------------------------------------------------------------------------------------
  Index Scan using foo_geom_idx on foo  (cost=0.00..8.29 rows=1 width=84)
    Index Cond: (the_geom  
&& '0101000000000000000000E03F000000000000E03F'::geometry)
(2 rows)

EXPLAIN SELECT * FROM foo WHERE the_geom = 'POINT(0.5 0.5)';
                                   QUERY PLAN
-------------------------------------------------------------------------------
  Seq Scan on foo  (cost=0.00..1839.00 rows=100 width=84)
    Filter: (the_geom  
= '0101000000000000000000E03F000000000000E03F'::geometry)
(2 rows)

-- Kevin

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