[postgis-tickets] [PostGIS] #5025: Inconsistent behavior with ST_Within across versions

[PostGIS]

#5025: Inconsistent behavior with ST_Within across versions
----------------------+---------------------------
  Reporter:  byrman   |      Owner:  pramsey
      Type:  defect   |     Status:  new
  Priority:  medium   |  Milestone:  PostGIS 3.0.7
 Component:  postgis  |    Version:  3.1.x
Resolution:           |   Keywords:
----------------------+---------------------------
Comment (by pramsey):

 Dispensing with all the index creation above simplifies things a little
 and just on my latest pg14/postgis3.2 installation we can at least get a
 workable issue that doesn't involve juggling docker images.
 {{{
 pramsey=# explain SELECT COUNT(*) FROM a, b WHERE ST_Within(a.geom,
 b.geom);
                            QUERY PLAN
 ----------------------------------------------------------------
  Aggregate  (cost=2505.26..2505.27 rows=1 width=8)
    ->  Nested Loop  (cost=0.00..2505.01 rows=100 width=0)
          Join Filter: st_within(a.geom, b.geom)
          ->  Seq Scan on b  (cost=0.00..1.01 rows=1 width=168)
          ->  Seq Scan on a  (cost=0.00..3.00 rows=100 width=40)
 (5 rows)

 pramsey=# CREATE INDEX a_3d_idx ON a USING GIST(geom
 gist_geometry_ops_nd);
 CREATE INDEX
 pramsey=# explain SELECT COUNT(*) FROM a, b WHERE ST_Within(a.geom,
 b.geom);
                                    QUERY PLAN
 --------------------------------------------------------------------------------
  Aggregate  (cost=34.42..34.43 rows=1 width=8)
    ->  Nested Loop  (cost=0.14..34.17 rows=100 width=0)
          ->  Seq Scan on b  (cost=0.00..1.01 rows=1 width=168)
          ->  Index Scan using a_3d_idx on a  (cost=0.14..33.16 rows=1
 width=40)
                Index Cond: (geom @@ b.geom)
                Filter: st_within(geom, b.geom)
 (6 rows)
 }}}
 There was some changes to the way 3D indexes worked in the last few
 revisions, from komzpa, I cannot recall when though, or even why. The
 question of "is something within in 3d" is a little open, particularly if
 the two operands are of different dimensionality.
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5025#comment:6>
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