[postgis-devel] [PostGIS] #1841: ST_Distance on PostGIS 2.0 is prohibitively slow

[PostGIS]

#1841: ST_Distance on PostGIS 2.0 is prohibitively slow
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 Reporter:  andrewxhill         |       Owner:  pramsey      
     Type:  enhancement         |      Status:  new          
 Priority:  medium              |   Milestone:  PostGIS 2.1.0
Component:  postgis             |     Version:  2.0.x        
 Keywords:  st_distance, speed  |  
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Comment(by nicklas):

 Hmm, is this really slow?

 This is more than 190000 pairwise distance-calculations. If the run-time
 is 6 minutes, 360000 ms it is about 2 ms per pair. With, in average 625
 points in each polygon, I am not sure it is very slow.

 If it would have been a brute force algorithm every distance pair would
 need 390000 vertex-combinations and almost as many edge-vertex
 combinations to compute.

 I do not have any PostGIS 1.4 installed to time brute force version, but I
 suspect it will be quite a lot slower.

 And I did it in 190000 ms, I love ssd :-)

 /Nicklas

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1841#comment:4>
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