4 files changed, 135 insertions, 0 deletions
diff --git a/src/test/regress/expected/constraints.out b/src/test/regress/expected/constraints.out
index e32cf8bb574..36ccbb5f155 100644
--- a/src/test/regress/expected/constraints.out
+++ b/src/test/regress/expected/constraints.out
@@ -446,6 +446,29 @@ SELECT * FROM UNIQUE_TBL;
 (7 rows)
 
 DROP TABLE UNIQUE_TBL;
+CREATE TABLE UNIQUE_TBL (i int UNIQUE NULLS NOT DISTINCT, t text);
+INSERT INTO UNIQUE_TBL VALUES (1, 'one');
+INSERT INTO UNIQUE_TBL VALUES (2, 'two');
+INSERT INTO UNIQUE_TBL VALUES (1, 'three');
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+DETAIL:  Key (i)=(1) already exists.
+INSERT INTO UNIQUE_TBL VALUES (4, 'four');
+INSERT INTO UNIQUE_TBL VALUES (5, 'one');
+INSERT INTO UNIQUE_TBL (t) VALUES ('six');
+INSERT INTO UNIQUE_TBL (t) VALUES ('seven');
+ERROR:  duplicate key value violates unique constraint "unique_tbl_i_key"
+DETAIL:  Key (i)=(null) already exists.
+SELECT * FROM UNIQUE_TBL;
+ i |  t   
+---+------
+ 1 | one
+ 2 | two
+ 4 | four
+ 5 | one
+   | six
+(5 rows)
+
+DROP TABLE UNIQUE_TBL;
 CREATE TABLE UNIQUE_TBL (i int, t text,
 	UNIQUE(i,t));
 INSERT INTO UNIQUE_TBL VALUES (1, 'one');
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index daf75dd5c44..53c8e830ceb 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -1272,6 +1272,67 @@ SELECT count(*) FROM tenk1 WHERE stringu1 = 'TVAAAA';
 DROP INDEX hash_tuplesort_idx;
 RESET maintenance_work_mem;
 --
+-- Test unique null behavior
+--
+CREATE TABLE unique_tbl (i int, t text);
+CREATE UNIQUE INDEX unique_idx1 ON unique_tbl (i) NULLS DISTINCT;
+CREATE UNIQUE INDEX unique_idx2 ON unique_tbl (i) NULLS NOT DISTINCT;
+INSERT INTO unique_tbl VALUES (1, 'one');
+INSERT INTO unique_tbl VALUES (2, 'two');
+INSERT INTO unique_tbl VALUES (3, 'three');
+INSERT INTO unique_tbl VALUES (4, 'four');
+INSERT INTO unique_tbl VALUES (5, 'one');
+INSERT INTO unique_tbl (t) VALUES ('six');
+INSERT INTO unique_tbl (t) VALUES ('seven');  -- error from unique_idx2
+ERROR:  duplicate key value violates unique constraint "unique_idx2"
+DETAIL:  Key (i)=(null) already exists.
+DROP INDEX unique_idx1, unique_idx2;
+INSERT INTO unique_tbl (t) VALUES ('seven');
+-- build indexes on filled table
+CREATE UNIQUE INDEX unique_idx3 ON unique_tbl (i) NULLS DISTINCT;  -- ok
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT;  -- error
+ERROR:  could not create unique index "unique_idx4"
+DETAIL:  Key (i)=(null) is duplicated.
+DELETE FROM unique_tbl WHERE t = 'seven';
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT;  -- ok now
+\d unique_tbl
+             Table "public.unique_tbl"
+ Column |  Type   | Collation | Nullable | Default 
+--------+---------+-----------+----------+---------
+ i      | integer |           |          | 
+ t      | text    |           |          | 
+Indexes:
+    "unique_idx3" UNIQUE, btree (i)
+    "unique_idx4" UNIQUE, btree (i) NULLS NOT DISTINCT
+
+\d unique_idx3
+      Index "public.unique_idx3"
+ Column |  Type   | Key? | Definition 
+--------+---------+------+------------
+ i      | integer | yes  | i
+unique, btree, for table "public.unique_tbl"
+
+\d unique_idx4
+      Index "public.unique_idx4"
+ Column |  Type   | Key? | Definition 
+--------+---------+------+------------
+ i      | integer | yes  | i
+unique nulls not distinct, btree, for table "public.unique_tbl"
+
+SELECT pg_get_indexdef('unique_idx3'::regclass);
+                           pg_get_indexdef                            
+----------------------------------------------------------------------
+ CREATE UNIQUE INDEX unique_idx3 ON public.unique_tbl USING btree (i)
+(1 row)
+
+SELECT pg_get_indexdef('unique_idx4'::regclass);
+                                     pg_get_indexdef                                     
+-----------------------------------------------------------------------------------------
+ CREATE UNIQUE INDEX unique_idx4 ON public.unique_tbl USING btree (i) NULLS NOT DISTINCT
+(1 row)
+
+DROP TABLE unique_tbl;
+--
 -- Test functional index
 --
 CREATE TABLE func_index_heap (f1 text, f2 text);
diff --git a/src/test/regress/sql/constraints.sql b/src/test/regress/sql/constraints.sql
index 458f8057785..34de0c969ae 100644
--- a/src/test/regress/sql/constraints.sql
+++ b/src/test/regress/sql/constraints.sql
@@ -306,6 +306,20 @@ SELECT * FROM UNIQUE_TBL;
 
 DROP TABLE UNIQUE_TBL;
 
+CREATE TABLE UNIQUE_TBL (i int UNIQUE NULLS NOT DISTINCT, t text);
+
+INSERT INTO UNIQUE_TBL VALUES (1, 'one');
+INSERT INTO UNIQUE_TBL VALUES (2, 'two');
+INSERT INTO UNIQUE_TBL VALUES (1, 'three');
+INSERT INTO UNIQUE_TBL VALUES (4, 'four');
+INSERT INTO UNIQUE_TBL VALUES (5, 'one');
+INSERT INTO UNIQUE_TBL (t) VALUES ('six');
+INSERT INTO UNIQUE_TBL (t) VALUES ('seven');
+
+SELECT * FROM UNIQUE_TBL;
+
+DROP TABLE UNIQUE_TBL;
+
 CREATE TABLE UNIQUE_TBL (i int, t text,
 	UNIQUE(i,t));
 
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index 8b353be16e0..9003950a1f7 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -388,6 +388,43 @@ RESET maintenance_work_mem;
 
 
 --
+-- Test unique null behavior
+--
+CREATE TABLE unique_tbl (i int, t text);
+
+CREATE UNIQUE INDEX unique_idx1 ON unique_tbl (i) NULLS DISTINCT;
+CREATE UNIQUE INDEX unique_idx2 ON unique_tbl (i) NULLS NOT DISTINCT;
+
+INSERT INTO unique_tbl VALUES (1, 'one');
+INSERT INTO unique_tbl VALUES (2, 'two');
+INSERT INTO unique_tbl VALUES (3, 'three');
+INSERT INTO unique_tbl VALUES (4, 'four');
+INSERT INTO unique_tbl VALUES (5, 'one');
+INSERT INTO unique_tbl (t) VALUES ('six');
+INSERT INTO unique_tbl (t) VALUES ('seven');  -- error from unique_idx2
+
+DROP INDEX unique_idx1, unique_idx2;
+
+INSERT INTO unique_tbl (t) VALUES ('seven');
+
+-- build indexes on filled table
+CREATE UNIQUE INDEX unique_idx3 ON unique_tbl (i) NULLS DISTINCT;  -- ok
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT;  -- error
+
+DELETE FROM unique_tbl WHERE t = 'seven';
+
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT;  -- ok now
+
+\d unique_tbl
+\d unique_idx3
+\d unique_idx4
+SELECT pg_get_indexdef('unique_idx3'::regclass);
+SELECT pg_get_indexdef('unique_idx4'::regclass);
+
+DROP TABLE unique_tbl;
+
+
+--
 -- Test functional index
 --
 CREATE TABLE func_index_heap (f1 text, f2 text);