[postgis-tickets] r16669 - Ensure index filters on expanded boxes are large enough to encompass

[Paul Ramsey]

Author: pramsey
Date: 2018-07-24 13:55:20 -0700 (Tue, 24 Jul 2018)
New Revision: 16669

Modified:
   branches/2.4/NEWS
   branches/2.4/postgis/geography_measurement.c
   branches/2.4/regress/tickets.sql
   branches/2.4/regress/tickets_expected
Log:
Ensure index filters on expanded boxes are large enough to encompass
the radii they are searching, references #4081


Modified: branches/2.4/NEWS
===================================================================
--- branches/2.4/NEWS	2018-07-24 20:50:08 UTC (rev 16668)
+++ branches/2.4/NEWS	2018-07-24 20:55:20 UTC (rev 16669)
@@ -15,6 +15,7 @@
   - #4090, PG 11 support (Paul Ramsey, Raúl Marín)
   - #3997, fix bug in lwgeom_median and avoid division by zero (Raúl Marín)
   - #4093, Inconsistent results from qsort callback (yugr)
+  - #4081, Geography DWithin() issues for certain cases (Paul Ramsey)
   - #4105, Parallel build of tarball (Bas Couwenberg)
 
 

Modified: branches/2.4/postgis/geography_measurement.c
===================================================================
--- branches/2.4/postgis/geography_measurement.c	2018-07-24 20:50:08 UTC (rev 16668)
+++ branches/2.4/postgis/geography_measurement.c	2018-07-24 20:55:20 UTC (rev 16669)
@@ -466,16 +466,20 @@
 {
 	GSERIALIZED *g = NULL;
 	GSERIALIZED *g_out = NULL;
-	double distance;
+	double unit_distance, distance;
 
 	/* Get a wholly-owned pointer to the geography */
 	g = PG_GETARG_GSERIALIZED_P_COPY(0);
 
 	/* Read our distance value and normalize to unit-sphere. */
-	distance = PG_GETARG_FLOAT8(1) / WGS84_RADIUS;
+	distance = PG_GETARG_FLOAT8(1);
+	/* Magic 1% expansion is to bridge difference between potential */
+	/* spheroidal input distance and fact that expanded box filter is */
+	/* calculated on sphere */
+	unit_distance = 1.01 * distance / WGS84_RADIUS;
 
 	/* Try the expansion */
-	g_out = gserialized_expand(g, distance);
+	g_out = gserialized_expand(g, unit_distance);
 
 	/* If the expansion fails, the return our input */
 	if ( g_out == NULL )

Modified: branches/2.4/regress/tickets.sql
===================================================================
--- branches/2.4/regress/tickets.sql	2018-07-24 20:50:08 UTC (rev 16668)
+++ branches/2.4/regress/tickets.sql	2018-07-24 20:55:20 UTC (rev 16669)
@@ -1032,5 +1032,14 @@
 --#4089
 select '#4089', st_astext(st_geomfromtwkb(st_AsTWKB(st_GeometryFromText('LINESTRING Z(1 1 1, 3 3 1)'), 1, 0, 0, false, true)));
 
+-- #4081
+select '#4081',
+ST_DWithin(a, b, 110575, true) as within_110575_true,
+ST_DWithin(a, b, 110576, true) as within_110576_true
+from (
+    select ST_GeogFromText('SRID=4326;POINT(1.0 2.0)') as a, ST_GeogFromText('SRID=4326;POINT(1.0 1.0)') as b
+) as points;
+
+
 -- Clean up
 DELETE FROM spatial_ref_sys;

Modified: branches/2.4/regress/tickets_expected
===================================================================
--- branches/2.4/regress/tickets_expected	2018-07-24 20:50:08 UTC (rev 16668)
+++ branches/2.4/regress/tickets_expected	2018-07-24 20:55:20 UTC (rev 16669)
@@ -309,3 +309,4 @@
 #4055a|4326
 #4055b|4326
 #4089|LINESTRING Z (1 1 1,3 3 1)
+#4081|f|t