diff --git a/Makefile b/Makefile
index 8fc69c3..c556e86 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@ REGRESS     = init tables points euler circle line ellipse poly path box index \
 			  contains_ops contains_ops_compat bounding_box_gist gnomo healpix \
 			  moc
 
-REGRESS_9_5 = index_9.5 # experimental for spoint3
+REGRESS_9_5 = index_9.5 knn # experimental for spoint3
 
 TESTS       = init_test tables points euler circle line ellipse poly path box index \
 			  contains_ops contains_ops_compat bounding_box_gist gnomo healpix \
@@ -81,11 +81,11 @@ has_explain_summary = $(if $(filter-out 9.%,$(pg_version)),y,n)
 #
 
 ## the use of spoint 3 is too experimental and preliminary:
-#ifeq ($(pg_version_9_5_plus),y)
-#	REGRESS += $(REGRESS_9_5)
-#	TESTS   += $(REGRESS_9_5)
-#	PGS_SQL += $(PGS_SQL_9_5)
-#endif
+ifeq ($(pg_version_9_5_plus),y)
+	REGRESS += $(REGRESS_9_5)
+	TESTS   += $(REGRESS_9_5)
+	PGS_SQL += $(PGS_SQL_9_5)
+endif
 
 crushtest: REGRESS += $(CRUSH_TESTS)
 crushtest: installcheck
diff --git a/expected/knn.out b/expected/knn.out
new file mode 100644
index 0000000..3cb22af
--- /dev/null
+++ b/expected/knn.out
@@ -0,0 +1,40 @@
+CREATE TABLE points (id int, p spoint, pos int);
+INSERT INTO points (id, p) SELECT x, spoint(random()*6.28, (2*random()-1)*1.57) FROM generate_series(1,314159) x;
+CREATE INDEX i ON points USING gist (p spoint3);
+SET enable_indexscan = true;
+EXPLAIN (costs off) SELECT p <-> spoint (0.2, 0.3) FROM points ORDER BY 1 LIMIT 10;
+                   QUERY PLAN                    
+-------------------------------------------------
+ Limit
+   ->  Index Only Scan using i on points
+         Order By: (p <-> '(0.2 , 0.3)'::spoint)
+(3 rows)
+
+UPDATE points SET pos = n FROM (SELECT id, row_number() OVER (ORDER BY p <-> spoint (0.2, 0.3)) n  FROM points ORDER BY p <-> spoint (0.2, 0.3) LIMIT 10) sel WHERE points.id = sel.id;
+SET enable_indexscan = false;
+SET enable_indexonlyscan = false;
+EXPLAIN (costs off) SELECT p <-> spoint (0.2, 0.3) FROM points ORDER BY 1 LIMIT 10;
+                    QUERY PLAN                     
+---------------------------------------------------
+ Limit
+   ->  Sort
+         Sort Key: ((p <-> '(0.2 , 0.3)'::spoint))
+         ->  Seq Scan on points
+(4 rows)
+
+SELECT pos, row_number() OVER (ORDER BY p <-> spoint (0.2, 0.3)) n  FROM points ORDER BY p <-> spoint (0.2, 0.3) LIMIT 10;
+ pos | n  
+-----+----
+   1 |  1
+   2 |  2
+   3 |  3
+   4 |  4
+   5 |  5
+   6 |  6
+   7 |  7
+   8 |  8
+   9 |  9
+  10 | 10
+(10 rows)
+
+DROP TABLE points;
diff --git a/sql/knn.sql b/sql/knn.sql
new file mode 100644
index 0000000..e49ddad
--- /dev/null
+++ b/sql/knn.sql
@@ -0,0 +1,12 @@
+CREATE TABLE points (id int, p spoint, pos int);
+INSERT INTO points (id, p) SELECT x, spoint(random()*6.28, (2*random()-1)*1.57) FROM generate_series(1,314159) x;
+CREATE INDEX i ON points USING gist (p spoint3);
+SET enable_indexscan = true;
+EXPLAIN (costs off) SELECT p <-> spoint (0.2, 0.3) FROM points ORDER BY 1 LIMIT 10;
+UPDATE points SET pos = n FROM (SELECT id, row_number() OVER (ORDER BY p <-> spoint (0.2, 0.3)) n  FROM points ORDER BY p <-> spoint (0.2, 0.3) LIMIT 10) sel WHERE points.id = sel.id;
+SET enable_indexscan = false;
+SET enable_indexonlyscan = false;
+EXPLAIN (costs off) SELECT p <-> spoint (0.2, 0.3) FROM points ORDER BY 1 LIMIT 10;
+SELECT pos, row_number() OVER (ORDER BY p <-> spoint (0.2, 0.3)) n  FROM points ORDER BY p <-> spoint (0.2, 0.3) LIMIT 10;
+DROP TABLE points;
+