[postgis-tickets] [PostGIS] #3617: ST_ClusterDbScan sometimes returns NULL cluster numbers

[PostGIS]

#3617: ST_ClusterDbScan sometimes returns NULL cluster numbers
---------------------+---------------------------
 Reporter:  robe     |      Owner:  pramsey
     Type:  defect   |     Status:  new
 Priority:  blocker  |  Milestone:  PostGIS 2.3.0
Component:  postgis  |    Version:  trunk
 Keywords:           |
---------------------+---------------------------
 In trying to troubleshoot issue #3612, I came across this other oddity.


 {{{
 SELECT ST_ClusterDBScan(geom,0,2) OVER()
 FROM (SELECT ST_Point(10*i,2) As geom
 FROM generate_series(1,10) i ) AS f;
 }}}


 Returns all nulls:


 {{{
  st_clusterdbscan
 ------------------
              NULL
              NULL
              NULL
              NULL
              NULL
              NULL
              NULL
              NULL
              NULL
              NULL
 (10 rows)

 }}}


 This is testing with:


 {{{
 POSTGIS="2.3.0dev r15043" GEOS="3.5.0-CAPI-1.9.0 r4090" PROJ="Rel. 4.9.1,
 04 March 2015" GDAL="GDAL 2.1.0, released 2016/04/25" LIBXML="2.7.8"
 LIBJSON="0.12" RASTER PostgreSQL 9.5.2, compiled by Visual C++ build 1800,
 64-bit
 }}}

 as well as


 {{{
 POSTGIS="2.3.0dev r15050" GEOS="3.5.0-CAPI-1.9.0 r4090" SFCGAL="1.3.0"
 PROJ="Rel. 4.9.1, 04 March 2015" GDAL="GDAL 2.1.0, released 2016/04/25"
 LIBXML="2.7.8" LIBJSON="0.12" (core procs from "2.3.0dev r15044" need
 upgrade) RASTER (raster procs from "2.3.0dev r15044" need upgrade) (sfcgal
 procs from "2.3.0dev r15044" need upgrade) PostgreSQL 9.6beta4, compiled
 by Visual C++ build 1800, 64-bit
 }}}

 and even testing under mingw


 {{{
 POSTGIS="2.3.0dev r15050" GEOS="3.5.0-CAPI-1.9.0 r4088" PROJ="Rel. 4.9.1,
 04 March 2015" GDAL="GDAL 2.1.0, released 2016/04/25" LIBXML="2.7.8"
 LIBJSON="0.12" RASTER PostgreSQL 9.6beta4 on x86_64-w64-mingw32, compiled
 by gcc.exe (x86_64-win32-seh-rev1, Built by MinGW-W64 project) 4.8.3,
 64-bit
 }}}


 I'm going to go thru my real data examples I've tested before to see
 what's up.  I'm thinking this might have to do with recent changes in this
 function since last I tested.

--
Ticket URL: <https://trac.osgeo.org/postgis/ticket/3617>
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