[geos-devel] [GEOS] #997: ST_Union performance degradation from GEOS 3.6.x -> 3.7.x

[GEOS]

#997: ST_Union performance degradation from GEOS 3.6.x -> 3.7.x
-------------------------+---------------------------
 Reporter:  greenlaw     |       Owner:  geos-devel@…
     Type:  defect       |      Status:  new
 Priority:  major        |   Milestone:
Component:  Default      |     Version:  3.7.0
 Severity:  Significant  |  Resolution:
 Keywords:  union        |
-------------------------+---------------------------

Comment (by pramsey):

 I'm not reproducing this locally. Using your data and my set up (3.8rc3,
 pg11, postgis3) I'm seeing times similar to your good runs on old GEOS on
 my wee laptop. You might want to ensure that your GEOS is built with -O3
 flags and not in full debug (-O0 -g) mode. That can cause 5x performance
 changes. I don't know *what* could cause your 40x regression.
 {{{
 postgis30=# select st_npoints(st_union(st_buffer(wkb_geometry,100))) from
 nws_haz_hang_201910 ;
  st_npoints
 ------------
     1112530
 (1 row)

 Time: 43946.265 ms (00:43.946)
 }}}

-- 
Ticket URL: <https://trac.osgeo.org/geos/ticket/997#comment:2>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).