[postgis-devel] [PostGIS] #1828: Estimate returned by geography_gist_selectivity results in slow query plan for ST_DWithin

[PostGIS]

#1828: Estimate returned by geography_gist_selectivity results in slow query plan
for ST_DWithin
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  Reporter:  realityexists  |       Owner:  mcayland     
      Type:  defect         |      Status:  reopened     
  Priority:  medium         |   Milestone:  PostGIS 2.0.2
 Component:  postgis        |     Version:  2.0.x        
Resolution:                 |    Keywords:               
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Comment(by pramsey):

 I made a lot of careless mistakes in that sequence, but the final problem
 ended up being quite subtle. r10731 I didn't fix it, I just reverted it.
 It's tricky and sensitive. The geodetic bounding box of a point, when
 converted to float and stored in the gserialized is slightly larger than a
 point. For a one-entry table, that means the histogram is not just a
 single box, but something bigger. Math explodes, unpleasantness ensues.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1828#comment:57>
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