[postgis-devel] [PostGIS] #1806: Extremely slow and CPU-intensive ST_MakeValid (ST_BuildArea) case

[PostGIS]

#1806: Extremely slow and CPU-intensive ST_MakeValid (ST_BuildArea) case
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 Reporter:  strk     |       Owner:  strk         
     Type:  defect   |      Status:  assigned     
 Priority:  high     |   Milestone:  PostGIS 2.0.1
Component:  postgis  |     Version:  2.0.x        
 Keywords:           |  
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Comment(by strk):

 polygonize finds 3536 polygons, so ST_BuildArea is stuck computing the
 symdifference between each of them and the aggregated result. While it
 goes on the time it takes to compute the symdifference grows. It starts
 with roughly 20 items per second. At iteration 1700 computes ~5
 symdifference per second... Every iteration has to rebuild the topology
 which was already built in the previous iteration.

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/1806#comment:5>
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