MWL#90, code cleanup

- Unify EXPLAIN printout for <subqueryN> tables with regular tables
- Update test results for <subqueryN> tables:
  s/unique_key/distinct_key/g
  s/1.0/100.0/ for "filtered" column

mysql-test/r/subselect3.result

@@ -1017,7 +1017,7 @@ update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	8	Using temporary; Using filesort
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	8	Using temporary; Using filesort
 1	PRIMARY	t21	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer
 1	PRIMARY	t22	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer
 2	SUBQUERY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where
@@ -1035,7 +1035,7 @@ select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) a
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	<subquery3>	eq_ref	unique_key	unique_key	5	func	1	
+2	DEPENDENT SUBQUERY	<subquery3>	eq_ref	distinct_key	distinct_key	5	func	1	
 3	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	2	
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 subq
@@ -1158,7 +1158,7 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 select * from t3 where a in (select a from t2);
@@ -1207,7 +1207,7 @@ insert into t3 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t1 A, t1 B, t1 C
 explain select * from t1, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30) and t1.a =3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 explain select straight_join * from t1 A, t1 B where A.a in (select a from t2);
@@ -1241,14 +1241,14 @@ insert into t0 values(1,1);
 explain select * from t0, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 create table t4 as select a as x, a as y from t1;
 explain select * from t0, t3 where (t3.a, t3.b) in (select x,y from t4) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where
 2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where
 drop table t0,t1,t2,t3,t4;
@@ -1274,14 +1274,14 @@ set @@optimizer_switch='firstmatch=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	10	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
 set @save_optimizer_search_depth=@@optimizer_search_depth;
 set @@optimizer_search_depth=63;
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	10	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=default;
@@ -1320,7 +1320,7 @@ insert into t2 select * from t2;
 explain select * from t1 where (a,b,c) in (select X.a, Y.a, Z.a from t2 X, t2 Y, t2 Z where X.b=33);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	15	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	15	func,func,func	1	
 2	SUBQUERY	X	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	6	Using join buffer
 2	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	6	Using join buffer
@@ -1393,7 +1393,7 @@ INNER JOIN t2 c ON c.idContact=cona.idContact
 WHERE cona.postalStripped='T2H3B2'
 	);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	1.00	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	100.00	
 1	PRIMARY	a	index	PRIMARY	PRIMARY	4	NULL	2	100.00	Using where; Using index; Using join buffer
 2	SUBQUERY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	

mysql-test/r/subselect3_jcl6.result

@@ -1021,7 +1021,7 @@ update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	8	Using temporary; Using filesort
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	8	Using temporary; Using filesort
 1	PRIMARY	t21	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer
 1	PRIMARY	t22	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer
 2	SUBQUERY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where
@@ -1039,7 +1039,7 @@ select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) a
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	X	ALL	NULL	NULL	NULL	NULL	2	
 2	DEPENDENT SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	<subquery3>	eq_ref	unique_key	unique_key	5	func	1	
+2	DEPENDENT SUBQUERY	<subquery3>	eq_ref	distinct_key	distinct_key	5	func	1	
 3	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	2	
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 subq
@@ -1162,7 +1162,7 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 select * from t3 where a in (select a from t2);
@@ -1211,7 +1211,7 @@ insert into t3 select A.a + 10*B.a, A.a + 10*B.a, 'filler' from t1 A, t1 B, t1 C
 explain select * from t1, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30) and t1.a =3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 explain select straight_join * from t1 A, t1 B where A.a in (select a from t2);
@@ -1245,14 +1245,14 @@ insert into t0 values(1,1);
 explain select * from t0, t3 where t3.a in (select a from t2) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 create table t4 as select a as x, a as y from t1;
 explain select * from t0, t3 where (t3.a, t3.b) in (select x,y from t4) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; Using join buffer
 2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where
 drop table t0,t1,t2,t3,t4;
@@ -1278,14 +1278,14 @@ set @@optimizer_switch='firstmatch=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	10	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
 set @save_optimizer_search_depth=@@optimizer_search_depth;
 set @@optimizer_search_depth=63;
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	10	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	100	
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=default;
@@ -1324,7 +1324,7 @@ insert into t2 select * from t2;
 explain select * from t1 where (a,b,c) in (select X.a, Y.a, Z.a from t2 X, t2 Y, t2 Z where X.b=33);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	15	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	15	func,func,func	1	
 2	SUBQUERY	X	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	Y	ALL	NULL	NULL	NULL	NULL	6	Using join buffer
 2	SUBQUERY	Z	ALL	NULL	NULL	NULL	NULL	6	Using join buffer
@@ -1397,7 +1397,7 @@ INNER JOIN t2 c ON c.idContact=cona.idContact
 WHERE cona.postalStripped='T2H3B2'
 	);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	1.00	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	100.00	
 1	PRIMARY	a	index	PRIMARY	PRIMARY	4	NULL	2	100.00	Using where; Using index; Using join buffer
 2	SUBQUERY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using join buffer

mysql-test/r/subselect4.result

@@ -216,7 +216,7 @@ FROM t2
 WHERE PTYPE = 'Design'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 PREPARE stmt FROM "EXPLAIN SELECT EMPNAME
@@ -231,13 +231,13 @@ WHERE EMPNUM IN
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	SIMPLE	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	SIMPLE	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 DEALLOCATE PREPARE stmt;
@@ -254,7 +254,7 @@ FROM t2
 WHERE PTYPE = 'Design'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 PREPARE stmt FROM "EXPLAIN SELECT EMPNAME
@@ -269,13 +269,13 @@ WHERE EMPNUM IN
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	t1_IDX	NULL	NULL	NULL	5	
-1	SIMPLE	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	SIMPLE	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 DEALLOCATE PREPARE stmt;
@@ -291,7 +291,7 @@ FROM t2
 WHERE PTYPE = 'Design'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 PREPARE stmt FROM "EXPLAIN SELECT EMPNAME
@@ -306,13 +306,13 @@ WHERE EMPNUM IN
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 EXECUTE stmt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	SIMPLE	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	SIMPLE	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
 DEALLOCATE PREPARE stmt;

mysql-test/r/subselect_mat.result

@@ -1200,7 +1200,7 @@ set @save_optimizer_switch=@@optimizer_switch;
 SET @@optimizer_switch='default,semijoin=on,materialization=on';
 EXPLAIN SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
 SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
@@ -1224,7 +1224,7 @@ SET @@optimizer_switch='default,semijoin=on,materialization=on';
 EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
 SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 pk

mysql-test/r/subselect_sj.result

@@ -848,7 +848,7 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	13	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	13	func,func	1	100.00	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using MRR
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
@@ -1017,7 +1017,7 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	8	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
 2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
 Warnings:
 Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))

mysql-test/r/subselect_sj2.result

@@ -32,7 +32,7 @@ a	b
 9	5
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	3	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	3	
 1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
 select * from t2 where b in (select a from t1);
@@ -74,7 +74,7 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	
 2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	
 set @save_ecp= @@engine_condition_pushdown;
@@ -101,7 +101,7 @@ set max_heap_table_size= @save_max_heap_table_size;
 explain select * from t1 where a in (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t2	index	b	b	5	NULL	10	Using index
 select * from t1;
 a	b
@@ -129,7 +129,7 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
@@ -163,7 +163,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
@@ -197,7 +197,7 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
@@ -231,7 +231,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
@@ -348,7 +348,7 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
 SELECT Name FROM t1 
 WHERE t1.Code IN (
@@ -696,7 +696,7 @@ The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)

mysql-test/r/subselect_sj2_jcl6.result

@@ -36,7 +36,7 @@ a	b
 9	5
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	3	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	3	
 1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using join buffer
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
 select * from t2 where b in (select a from t1);
@@ -78,7 +78,7 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	10	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
 1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	Using join buffer
 2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	
 set @save_ecp= @@engine_condition_pushdown;
@@ -105,7 +105,7 @@ set max_heap_table_size= @save_max_heap_table_size;
 explain select * from t1 where a in (select b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t2	index	b	b	5	NULL	10	Using index
 select * from t1;
 a	b
@@ -133,7 +133,7 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
@@ -167,7 +167,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
@@ -201,7 +201,7 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	22	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
@@ -235,7 +235,7 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
@@ -352,7 +352,7 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
 2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
 SELECT Name FROM t1 
 WHERE t1.Code IN (
@@ -702,7 +702,7 @@ The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)

mysql-test/r/subselect_sj_jcl6.result

@@ -852,7 +852,7 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	13	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	13	func,func	1	100.00	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using MRR
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
@@ -1021,7 +1021,7 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	8	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
 2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
 Warnings:
 Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))

mysql-test/r/subselect_sj_mat.result

@@ -39,7 +39,7 @@ explain extended
 select * from t1 where a1 in (select b1 from t2 where b1 > '0');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	9	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	9	func	1	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
 Warnings:
 Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b1` > '0'))
@@ -285,8 +285,8 @@ where (a1, a2) in (select b1, b2 from t2 where b1 >  '0') and
 where (c1, c2) in (select b1, b2 from t2i where b2 > '0'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	18	func	1	1.00	
-1	PRIMARY	<subquery3>	eq_ref	unique_key	unique_key	18	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
 3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 3	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	it2i3	18	NULL	5	80.00	Using where; Using index; Using join buffer
@@ -306,8 +306,8 @@ where (a1, a2) in (select b1, b2 from t2i where b1 >  '0') and
 where (c1, c2) in (select b1, b2 from t2i where b2 > '0'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1i	index	it1i1,it1i2,it1i3	#	#	#	3	100.00	#
-1	PRIMARY	<subquery2>	eq_ref	unique_key	#	#	#	1	1.00	#
-1	PRIMARY	<subquery3>	eq_ref	unique_key	#	#	#	1	1.00	#
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	#	#	#	1	100.00	#
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	#	#	#	1	100.00	#
 2	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	#	#	#	5	100.00	#
 3	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	#	#	#	5	100.00	#
 3	SUBQUERY	t3i	index	it3i1,it3i2,it3i3	#	#	#	4	75.00	#
@@ -329,8 +329,8 @@ b2 in (select c2 from t3 where c2 LIKE '%03')) and
 where (c1, c2) in (select b1, b2 from t2i where b2 > '0'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	18	func	1	1.00	
-1	PRIMARY	<subquery5>	eq_ref	unique_key	unique_key	18	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
+1	PRIMARY	<subquery5>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
 5	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 5	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	it2i3	18	NULL	5	80.00	Using where; Using index; Using join buffer
@@ -356,7 +356,7 @@ where (c1, c2) in (select b1, b2 from t2i where b2 > '0'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Start temporary
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; End temporary; Using join buffer
-1	PRIMARY	<subquery5>	eq_ref	unique_key	unique_key	18	func	1	1.00	
+1	PRIMARY	<subquery5>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
 5	SUBQUERY	t3c	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 5	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	it2i3	18	NULL	5	80.00	Using where; Using index; Using join buffer
 4	SUBQUERY	t3b	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
@@ -395,8 +395,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 4	SUBQUERY	t3	ALL	NULL	#	#	#	4	100.00	#
 3	SUBQUERY	t3	ALL	NULL	#	#	#	4	100.00	#
 7	UNION	t1i	index	it1i1,it1i2,it1i3	#	#	#	3	100.00	#
-7	UNION	<subquery8>	eq_ref	unique_key	#	#	#	1	1.00	#
-7	UNION	<subquery9>	eq_ref	unique_key	#	#	#	1	1.00	#
+7	UNION	<subquery8>	eq_ref	distinct_key	#	#	#	1	100.00	#
+7	UNION	<subquery9>	eq_ref	distinct_key	#	#	#	1	100.00	#
 8	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	#	#	#	5	100.00	#
 9	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	#	#	#	5	100.00	#
 9	SUBQUERY	t3i	index	it3i1,it3i2,it3i3	#	#	#	4	75.00	#
@@ -425,7 +425,7 @@ where (a1, a2) in (select * from t1 where a1 > '0' UNION select * from t2 where
 where (c1, c2) in (select b1, b2 from t2i where b2 > '0'));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-1	PRIMARY	<subquery4>	eq_ref	unique_key	unique_key	18	func	1	1.00	
+1	PRIMARY	<subquery4>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
 4	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 4	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	it2i3	18	NULL	5	80.00	Using where; Using index; Using join buffer
 2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
@@ -449,7 +449,7 @@ a1 = c1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where; Using join buffer
-1	PRIMARY	<subquery4>	eq_ref	unique_key	unique_key	18	func	1	1.00	
+1	PRIMARY	<subquery4>	eq_ref	distinct_key	distinct_key	18	func,func	1	100.00	
 4	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 4	SUBQUERY	t2i	index	it2i1,it2i2,it2i3	it2i3	18	NULL	5	80.00	Using where; Using index; Using join buffer
 2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
@@ -634,7 +634,7 @@ from t1_16
 where a1 in (select substring(b1,1,16) from t2_16 where b1 > '0');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_16	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	20	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	20	func	1	100.00	Using where
 2	SUBQUERY	t2_16	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
 Note	1003	select left(`test`.`t1_16`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_16`.`a2`,7) AS `left(a2,7)` from `test`.`t1_16` semi join (`test`.`t2_16`) where ((`test`.`t2_16`.`b1` > '0') and (`test`.`t1_16`.`a1` = substr(`test`.`t2_16`.`b1`,1,16)))
@@ -749,7 +749,7 @@ from t1_512
 where a1 in (select substring(b1,1,512) from t2_512 where b1 > '0');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_512	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	517	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	517	func	1	100.00	Using where
 2	SUBQUERY	t2_512	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
 Note	1003	select left(`test`.`t1_512`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_512`.`a2`,7) AS `left(a2,7)` from `test`.`t1_512` semi join (`test`.`t2_512`) where ((`test`.`t2_512`.`b1` > '0') and (`test`.`t1_512`.`a1` = substr(`test`.`t2_512`.`b1`,1,512)))
@@ -845,7 +845,7 @@ from t1_1024
 where a1 in (select substring(b1,1,1024) from t2_1024 where b1 > '0');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	15	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	NULL	distinct_key	15	func,func	1	100.00	Using where
 2	SUBQUERY	t2_1024	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
 Note	1003	select left(`test`.`t1_1024`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1024`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1024` semi join (`test`.`t2_1024`) where ((`test`.`t2_1024`.`b1` > '0') and (`test`.`t1_1024`.`a1` = substr(`test`.`t2_1024`.`b1`,1,1024)))
@@ -939,7 +939,7 @@ from t1_1025
 where a1 in (select substring(b1,1,1025) from t2_1025 where b1 > '0');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	15	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	NULL	distinct_key	15	func,func	1	100.00	Using where
 2	SUBQUERY	t2_1025	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 Warnings:
 Note	1003	select left(`test`.`t1_1025`.`a1`,7) AS `left(a1,7)`,left(`test`.`t1_1025`.`a2`,7) AS `left(a2,7)` from `test`.`t1_1025` semi join (`test`.`t2_1025`) where ((`test`.`t2_1025`.`b1` > '0') and (`test`.`t1_1025`.`a1` = substr(`test`.`t2_1025`.`b1`,1,1025)))
@@ -988,7 +988,7 @@ from t1bit
 where (a1, a2) in (select b1, b2 from t2bit);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1bit	ALL	NULL	NULL	NULL	NULL	3	100.00	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	10	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	100.00	
 2	SUBQUERY	t2bit	ALL	NULL	NULL	NULL	NULL	3	100.00	
 Warnings:
 Note	1003	select conv(`test`.`t1bit`.`a1`,10,2) AS `bin(a1)`,conv(`test`.`t1bit`.`a2`,10,2) AS `bin(a2)` from `test`.`t1bit` semi join (`test`.`t2bit`) where 1
@@ -1059,7 +1059,7 @@ insert into t3 values (30);
 explain extended
 select a from t1 where a in (select c from t2 where d >= 20);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	6	1.00	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	6	100.00	
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	7	100.00	Using where; Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where
 Warnings:
@@ -1074,7 +1074,7 @@ create index it1a on t1(a);
 explain extended
 select a from t1 where a in (select c from t2 where d >= 20);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	6	1.00	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	6	100.00	
 1	PRIMARY	t1	ref	it1a	it1a	4	test.t2.c	2	100.00	Using index
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	100.00	Using where
 Warnings:
@@ -1090,7 +1090,7 @@ explain extended
 select a from t1 where a in (select c from t2 where d >= 20);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	index	it1a	it1a	4	NULL	7	100.00	Using index
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	4	func	1	1.00	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	4	func	1	100.00	
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	7	100.00	Using where
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`d` >= 20))
@@ -1217,7 +1217,7 @@ insert into t1 values ('aa', 'aaaa');
 explain select a,b from t1 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	3	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	Using where
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
 select a,b from t1 where b in (select a from t1);
 a	b
@@ -1238,7 +1238,7 @@ set @save_optimizer_switch=@@optimizer_switch;
 SET @@optimizer_switch='default,semijoin=on,materialization=on';
 EXPLAIN SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<subquery2>	ALL	unique_key	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
 SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
@@ -1262,7 +1262,7 @@ SET @@optimizer_switch='default,semijoin=on,materialization=on';
 EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	<subquery2>	eq_ref	unique_key	unique_key	5	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
 SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 pk

sql/opt_subselect.cc

@@ -2722,6 +2722,16 @@ bool setup_sj_materialization(JOIN_TAB *sjm_tab)
       cur_ref_buff+= cur_key_part->store_length;
     }
     *ref_key= NULL; /* End marker. */
+      
+    /*
+      We don't ever have guarded conditions for SJM tables, but code at SQL
+      layer depends on cond_guards array being alloced.
+    */
+    if (!(tab_ref->cond_guards= (bool**) thd->calloc(sizeof(uint*)*tmp_key_parts)))
+    {
+      DBUG_RETURN(TRUE);
+    }
+
     tab_ref->key_err= 1;
     tab_ref->key_parts= tmp_key_parts;
     sjm->tab_ref= tab_ref;

sql/sql_select.cc

@@ -6044,12 +6044,15 @@ get_best_combination(JOIN *join)
       j->use_join_cache= FALSE;
       j->on_expr_ref= (Item**) &null_ptr;
       j->cache= NULL;
+      j->keys= key_map(1); // The unique index is always in 'possible keys' in EXPLAIN
+
 
       /*
         2. Proceed with processing SJM nest's join tabs, putting them into the
            sub-order
       */
       SJ_MATERIALIZATION_INFO *sjm= cur_pos->table->emb_sj_nest->sj_mat_info;
+      j->records= j->records_read= sjm->is_sj_scan? sjm->rows : 1;
       JOIN_TAB *jt= (JOIN_TAB*)join->thd->alloc(sizeof(JOIN_TAB) * sjm->tables);
       JOIN_TAB_RANGE *jt_range= new JOIN_TAB_RANGE;
       jt_range->start= jt;
@@ -18337,6 +18340,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
                                                     join->select_lex->type;
       item_list.push_back(new Item_string(stype, strlen(stype), cs));
       
+#if 0
       /* 
         Special processing for SJ-Materialization nests: print the fake table
         and delay printing of the SJM nest contents until later.
@@ -18416,6 +18420,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
         //i += join->best_positions[i].n_sj_tables-1;
         goto loop_end;
       }
+#endif      
 
       if (tab->type == JT_ALL && tab->select && tab->select->quick)
       {
@@ -18437,6 +18442,16 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 			     table->derived_select_number);
 	item_list.push_back(new Item_string(table_name_buffer, len, cs));
       }
+      else if (tab->bush_children)
+      {
+        JOIN_TAB *ctab= tab->bush_children->start;
+        /* table */
+        int len= my_snprintf(table_name_buffer, 
+                             sizeof(table_name_buffer)-1,
+                             "<subquery%d>", 
+                             ctab->emb_sj_nest->sj_subq_pred->get_identifier());
+	item_list.push_back(new Item_string(table_name_buffer, len, cs));
+      }
       else
       {
         TABLE_LIST *real_table= table->pos_in_table_list; 
@@ -18531,7 +18546,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
       }
       else
       {
-        if (table_list->schema_table &&
+        if (table_list && /* SJM bushes don't have table_list */
+            table_list->schema_table &&
             table_list->schema_table->i_s_requested_object & OPTIMIZE_I_S_TABLE)
         {
           const char *tmp_buff;
@@ -18562,7 +18578,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
       }
       
       /* Add "rows" field to item_list. */
-      if (table_list->schema_table)
+      if (table_list /* SJM bushes don't have table_list */ &&
+          table_list->schema_table)
       {
         /* in_rows */
         if (join->thd->lex->describe & DESCRIBE_EXTENDED)
@@ -18570,6 +18587,13 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
         /* rows */
         item_list.push_back(item_null);
       }
+     // else if (tab->bush_children)
+     // {
+     //   /* psergey-todo */
+     //   SJ_MATERIALIZATION_INFO *sjm= tab->bush_children->start->emb_sj_nest->sj_mat_info;
+//
+     //   ha_rows rows= is_scan ?  ctab->emb_sj_nest->sj_mat_info->rows : 1;
+     // }
       else
       {
         ha_rows examined_rows;
@@ -18685,7 +18709,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
               extra.append(STRING_WITH_LEN("; Using where"));
           }
 	}
-        if (table_list->schema_table &&
+        if (table_list /* SJM bushes don't have table_list */ &&
+            table_list->schema_table &&
             table_list->schema_table->i_s_requested_object & OPTIMIZE_I_S_TABLE)
         {
           if (!table_list->table_open_method)
@@ -18787,7 +18812,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
         }
 	item_list.push_back(new Item_string(str, len, cs));
       }
-    loop_end:
+    //loop_end:
     /* psergey2
        if (i+1 == end_table && sjm_nests_cur != sjm_nests_end)
        {