MWL#68 Subquery optimization: Efficient NOT IN execution with NULLs

Automerge with 5.3-subqueries

mysql-test/r/join_cache.result

@@ -4142,3 +4142,46 @@ c1	c2	c1	c2	LENGTH(t2.c1)	LENGTH(t2.c2)
 2	2	tt	uu	2	2
 set join_cache_level=default;
 DROP TABLE t1,t2;
+#
+# Bug #51092: linked join buffer is used for a 3-way cross join query 
+#             that selects only records of the first table
+#
+create table t1 (a int, b int);
+insert into t1 values (1,1),(2,2);
+create table t2 (a int, b int);
+insert into t2 values (1,1),(2,2);
+create table t3 (a int, b int);
+insert into t3 values (1,1),(2,2);
+explain select t1.* from t1,t2,t3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	Using join buffer
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using join buffer
+select t1.* from t1,t2,t3;
+a	b
+1	1
+2	2
+1	1
+2	2
+1	1
+2	2
+1	1
+2	2
+set join_cache_level=2;
+explain select t1.* from t1,t2,t3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	Using join buffer
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using join buffer
+select t1.* from t1,t2,t3;
+a	b
+1	1
+2	2
+1	1
+2	2
+1	1
+2	2
+1	1
+2	2
+set join_cache_level=default;
+drop table t1,t2,t3;

mysql-test/r/subselect_sj.result

@@ -824,3 +824,50 @@ a
 3
 2
 drop table t1, t2, t3;
+# 
+# Bug#49198 Wrong result for second call of procedure
+#           with view in subselect.
+# 
+CREATE TABLE t1 (t1field integer, primary key (t1field));
+CREATE TABLE t2 (t2field integer, primary key (t2field));
+CREATE TABLE t3 (t3field integer, primary key (t3field));
+CREATE VIEW v2 AS SELECT * FROM t2;
+CREATE VIEW v3 AS SELECT * FROM t3;
+INSERT INTO t1 VALUES(1),(2);
+INSERT INTO t2 VALUES(1),(2);
+INSERT INTO t3 VALUES(1),(2);
+PREPARE stmt FROM
+"
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2);
+";
+EXECUTE stmt;
+t1field
+1
+2
+EXECUTE stmt;
+t1field
+1
+2
+PREPARE stmt FROM
+"
+EXPLAIN
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2)
+  AND t1field IN (SELECT * FROM v3)
+";
+EXECUTE stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	PRIMARY	PRIMARY	4	NULL	2	Using index
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+EXECUTE stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	2	Using index
+1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+DROP TABLE t1, t2, t3;
+DROP VIEW v2, v3;
+# End of Bug#49198

mysql-test/r/subselect_sj2.result

@@ -264,8 +264,8 @@ explain select *
 from t0 where a in
 (select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	t1	index	NULL	a	5	NULL	10	Using index; Start temporary; Using join buffer
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Start temporary
+1	PRIMARY	t1	index	NULL	a	5	NULL	10	Using index; Using join buffer
 1	PRIMARY	t2	ref	a	a	5	test.t1.a	1	Using index
 1	PRIMARY	t3	ref	a	a	5	test.t1.a	1	Using where; Using index; End temporary
 drop table t0, t1,t2,t3;

mysql-test/r/subselect_sj2_jcl6.result

@@ -268,8 +268,8 @@ explain select *
 from t0 where a in
 (select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	t1	index	NULL	a	5	NULL	10	Using index; Start temporary; Using join buffer
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Start temporary
+1	PRIMARY	t1	index	NULL	a	5	NULL	10	Using index; Using join buffer
 1	PRIMARY	t2	ref	a	a	5	test.t1.a	1	Using index
 1	PRIMARY	t3	ref	a	a	5	test.t1.a	1	Using where; Using index; End temporary
 drop table t0, t1,t2,t3;
@@ -421,20 +421,23 @@ explain extended select * from t0
 where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
 t1.b=t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	
-1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Start temporary; Using join buffer
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Start temporary
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using join buffer
 1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary; Using join buffer
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t2`.`a` = `test`.`t0`.`a`))
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
-
+# Not anymore:
 # The following query gives wrong result due to Bug#49129
 select * from t0 where t0.a in 
 (select t1.a from t1, t2 where t2.a=t0.a and t1.b=t2.b);
 a
 0
+1
+2
+3
 drop table t0, t1, t2;
 CREATE TABLE t1 (
 id int(11) NOT NULL,
@@ -713,9 +716,9 @@ c2 in (select 1 from t3, t2) and
 c1 in (select convert(c6,char(1)) from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	FirstMatch(t2)
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using join buffer
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	FirstMatch(t2); Using join buffer
 drop table t2, t3;
 set join_cache_level=default;
 show variables like 'join_cache_level';

mysql-test/r/subselect_sj_jcl6.result

@@ -374,8 +374,8 @@ WHERE PNUM IN
 (SELECT PNUM  FROM PROJ));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	STAFF	ALL	NULL	NULL	NULL	NULL	5	
-1	PRIMARY	PROJ	ALL	NULL	NULL	NULL	NULL	6	
-1	PRIMARY	WORKS	ALL	NULL	NULL	NULL	NULL	12	Using where; FirstMatch(STAFF)
+1	PRIMARY	PROJ	ALL	NULL	NULL	NULL	NULL	6	Using join buffer
+1	PRIMARY	WORKS	ALL	NULL	NULL	NULL	NULL	12	Using where; FirstMatch(STAFF); Using join buffer
 SELECT EMPNUM, EMPNAME
 FROM STAFF
 WHERE EMPNUM IN
@@ -828,6 +828,84 @@ a
 3
 2
 drop table t1, t2, t3;
+# 
+# Bug#49198 Wrong result for second call of procedure
+#           with view in subselect.
+# 
+CREATE TABLE t1 (t1field integer, primary key (t1field));
+CREATE TABLE t2 (t2field integer, primary key (t2field));
+CREATE TABLE t3 (t3field integer, primary key (t3field));
+CREATE VIEW v2 AS SELECT * FROM t2;
+CREATE VIEW v3 AS SELECT * FROM t3;
+INSERT INTO t1 VALUES(1),(2);
+INSERT INTO t2 VALUES(1),(2);
+INSERT INTO t3 VALUES(1),(2);
+PREPARE stmt FROM
+"
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2);
+";
+EXECUTE stmt;
+t1field
+1
+2
+EXECUTE stmt;
+t1field
+1
+2
+PREPARE stmt FROM
+"
+EXPLAIN
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2)
+  AND t1field IN (SELECT * FROM v3)
+";
+EXECUTE stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	index	PRIMARY	PRIMARY	4	NULL	2	Using index
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+EXECUTE stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	2	Using index
+1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.t1field	1	Using index
+DROP TABLE t1, t2, t3;
+DROP VIEW v2, v3;
+# End of Bug#49198
+#
+# BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off
+#
+CREATE TABLE t0 (a INT);
+INSERT INTO t0 VALUES (0),(1),(2),(3),(4);
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 SELECT a, a from t0;
+CREATE TABLE t2 (a INT, b INT, PRIMARY KEY(a));
+INSERT INTO t2 SELECT * FROM t1;
+UPDATE t1 SET a=3, b=11 WHERE a=4;
+UPDATE t2 SET b=11 WHERE a=3;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='firstmatch=off';
+The following should use a join order of t0,t1,t2, with DuplicateElimination:
+explain
+SELECT * FROM t0 WHERE t0.a IN 
+(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	Start temporary
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	Using join buffer
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	Using where; End temporary; Using join buffer
+SELECT * FROM t0 WHERE t0.a IN 
+(SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+a
+0
+1
+2
+3
+set optimizer_switch=@save_optimizer_switch;
+drop table t0, t1, t2;
+# End
 set join_cache_level=default;
 show variables like 'join_cache_level';
 Variable_name	Value

mysql-test/suite/pbxt/r/group_min_max.result

@@ -2257,7 +2257,7 @@ EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE
 a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
+2	SUBQUERY	t1	index	NULL	a	10	NULL	15	Using index
 EXPLAIN SELECT 1 FROM t1 AS t1_outer GROUP BY a HAVING 
 a > (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/suite/pbxt/r/subselect.result

@@ -1293,31 +1293,31 @@ a
 4
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
+1	PRIMARY	t2	index	PRIMARY	PRIMARY	4	NULL	4	100.00	Using index
+1	PRIMARY	t1	index	PRIMARY	PRIMARY	4	NULL	4	75.00	Using where; Using index; Using join buffer
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY)))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t2` where (`test`.`t1`.`a` = `test`.`t2`.`a`)
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
 2
 4
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	unique_subquery	PRIMARY	PRIMARY	4	func	1	100.00	Using where
+1	PRIMARY	t2	index	PRIMARY	PRIMARY	4	NULL	4	100.00	Using index
+1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	75.00	Using where; Using join buffer
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<primary_index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on PRIMARY where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 a
 2
 3
 explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	eq_ref	PRIMARY	PRIMARY	4	func	1	100.00	
-2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
+1	PRIMARY	t2	index	PRIMARY	PRIMARY	4	NULL	4	100.00	Using index
+1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	75.00	Using where; Using join buffer
+1	PRIMARY	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.b	1	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t1` join `test`.`t3` join `test`.`t2` where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`))
 drop table t1, t2, t3;
 create table t1 (a int, b int, index a (a,b));
 create table t2 (a int, index a (a));
@@ -1332,31 +1332,31 @@ a
 4
 explain extended select * from t2 where t2.a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1	100.00	Using index
+1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using index
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	1	100.00	Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a)))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where (`test`.`t1`.`a` = `test`.`t2`.`a`)
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
 2
 4
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1	100.00	Using index; Using where
+1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using index
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	1	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 a
 2
 3
 explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	ref	a	a	5	func	1	100.00	Using index
-2	DEPENDENT SUBQUERY	t3	ref	a	a	5	test.t1.b	1	100.00	Using index
+1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using index
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	1	100.00	Using index
+1	PRIMARY	t3	ref	a	a	5	test.t1.b	1	100.00	Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(select 1 AS `Not_used` from `test`.`t1` join `test`.`t3` where ((`test`.`t3`.`a` = `test`.`t1`.`b`) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1` join `test`.`t3`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t3`.`a` = `test`.`t1`.`b`))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a
@@ -1369,10 +1369,10 @@ a
 4
 explain extended select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	index_subquery	a	a	5	func	1	100.00	Using index; Using where
+1	PRIMARY	t2	index	a	a	5	NULL	4	100.00	Using index
+1	PRIMARY	t1	ref	a	a	5	test.t2.a	1	100.00	Using where; Using index; FirstMatch(t2)
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(<index_lookup>(<cache>(`test`.`t2`.`a`) in t1 on a where ((`test`.`t1`.`b` <> 30) and (<cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`)))))
+Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`a` = `test`.`t2`.`a`) and (`test`.`t1`.`b` <> 30))
 drop table t1, t2, t3;
 create table t1 (a int, b int);
 create table t2 (a int, b int);
@@ -2823,10 +2823,10 @@ Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one` AS `one`,`test`.`t2`.`two` AS `two` from `test`.`t2` where ((`test`.`t2`.`flag` = '0') and trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`)))) having (trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`))))) AS `test` from `test`.`t1`
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	Using where
-2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` where <in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one` AS `one`,`test`.`t2`.`two` AS `two` from `test`.`t2` where ((`test`.`t2`.`flag` = 'N') and (<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) and (<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`))))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
@@ -3412,7 +3412,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3423,7 +3423,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	Using filesort
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4213,8 +4213,8 @@ CREATE INDEX I1 ON t1 (a);
 CREATE INDEX I2 ON t1 (b);
 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	Using where
-2	DEPENDENT SUBQUERY	t1	index_subquery	I1	I1	2	func	1	Using index; Using where
+1	PRIMARY	t1	index	I1	I1	2	NULL	2	Using index; LooseScan
+1	PRIMARY	t1	ref	I2	I2	13	test.t1.a	1	Using where
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1);
 a	b
 CREATE TABLE t2 (a VARCHAR(1), b VARCHAR(10));
@@ -4223,15 +4223,15 @@ CREATE INDEX I1 ON t2 (a);
 CREATE INDEX I2 ON t2 (b);
 EXPLAIN SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	t2	index_subquery	I1	I1	4	func	1	Using index; Using where
+1	PRIMARY	t2	index	I1	I1	4	NULL	2	Using index; LooseScan
+1	PRIMARY	t2	ref	I2	I2	13	test.t2.a	1	Using where
 SELECT a,b FROM t2 WHERE b IN (SELECT a FROM t2);
 a	b
 EXPLAIN
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	t1	index_subquery	I1	I1	2	func	1	Using index; Using where
+1	PRIMARY	t1	index	I1	I1	2	NULL	2	Using where; Using index; LooseScan
+1	PRIMARY	t1	ref	I2	I2	13	test.t1.a	1	Using where
 SELECT a,b FROM t1 WHERE b IN (SELECT a FROM t1 WHERE LENGTH(a)<500);
 a	b
 DROP TABLE t1,t2;

mysql-test/t/join_cache.test

@@ -1823,3 +1823,27 @@ SELECT t1.*, t2.*, LENGTH(t2.c1), LENGTH(t2.c2) FROM t1,t2
 set join_cache_level=default;
 
 DROP TABLE t1,t2;
+
+--echo #
+--echo # Bug #51092: linked join buffer is used for a 3-way cross join query 
+--echo #             that selects only records of the first table
+--echo #
+
+create table t1 (a int, b int);
+insert into t1 values (1,1),(2,2);
+create table t2 (a int, b int);
+insert into t2 values (1,1),(2,2);
+create table t3 (a int, b int);
+insert into t3 values (1,1),(2,2);
+
+explain select t1.* from t1,t2,t3;
+select t1.* from t1,t2,t3; 
+
+set join_cache_level=2;
+
+explain select t1.* from t1,t2,t3;
+select t1.* from t1,t2,t3; 
+
+set join_cache_level=default;
+
+drop table t1,t2,t3;

mysql-test/t/subselect_sj.test

@@ -728,3 +728,45 @@ where a in (select c from t2 where d >= some(select e from t3 where b=e));
 
 drop table t1, t2, t3;
 
+--echo # 
+--echo # Bug#49198 Wrong result for second call of procedure
+--echo #           with view in subselect.
+--echo # 
+
+CREATE TABLE t1 (t1field integer, primary key (t1field));
+CREATE TABLE t2 (t2field integer, primary key (t2field));
+CREATE TABLE t3 (t3field integer, primary key (t3field));
+
+CREATE VIEW v2 AS SELECT * FROM t2;
+CREATE VIEW v3 AS SELECT * FROM t3;
+
+INSERT INTO t1 VALUES(1),(2);
+INSERT INTO t2 VALUES(1),(2);
+INSERT INTO t3 VALUES(1),(2);
+
+PREPARE stmt FROM
+"
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2);
+";
+
+EXECUTE stmt;
+EXECUTE stmt;
+
+PREPARE stmt FROM
+"
+EXPLAIN
+SELECT t1field
+FROM t1
+WHERE t1field IN (SELECT * FROM v2)
+  AND t1field IN (SELECT * FROM v3)
+";
+
+EXECUTE stmt;
+EXECUTE stmt;
+
+DROP TABLE t1, t2, t3;
+DROP VIEW v2, v3;
+
+--echo # End of Bug#49198

mysql-test/t/subselect_sj2.test

@@ -583,7 +583,7 @@ update t2 set b=11 where a=3;
 
 if (`select @@join_cache_level=6`)
 {
-  --echo 
+  --echo # Not anymore:
   --echo # The following query gives wrong result due to Bug#49129
 }
 select * from t0 where t0.a in 

mysql-test/t/subselect_sj_jcl6.test

@@ -7,5 +7,33 @@ show variables like 'join_cache_level';
 
 --source t/subselect_sj.test
 
+--echo #
+--echo # BUG#49129: Wrong result with IN-subquery with join_cache_level=6 and firstmatch=off
+--echo #
+CREATE TABLE t0 (a INT);
+INSERT INTO t0 VALUES (0),(1),(2),(3),(4);
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 SELECT a, a from t0;
+CREATE TABLE t2 (a INT, b INT, PRIMARY KEY(a));
+INSERT INTO t2 SELECT * FROM t1;
+UPDATE t1 SET a=3, b=11 WHERE a=4;
+UPDATE t2 SET b=11 WHERE a=3;
+
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='firstmatch=off';
+
+--echo The following should use a join order of t0,t1,t2, with DuplicateElimination:
+explain
+SELECT * FROM t0 WHERE t0.a IN 
+  (SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+
+SELECT * FROM t0 WHERE t0.a IN 
+  (SELECT t1.a FROM t1, t2 WHERE t2.a=t0.a AND t1.b=t2.b);
+
+set optimizer_switch=@save_optimizer_switch;
+drop table t0, t1, t2;
+
+--echo # End
+
 set join_cache_level=default;
 show variables like 'join_cache_level';

sql/item.cc

@@ -6491,11 +6491,9 @@ void Item_outer_ref::fix_after_pullout(st_select_lex *new_parent, Item **ref)
 
 void Item_ref::fix_after_pullout(st_select_lex *new_parent, Item **refptr)
 {
-  if (depended_from == new_parent)
-  {
   (*ref)->fix_after_pullout(new_parent, ref);
+  if (depended_from == new_parent)
     depended_from= NULL;
-  }
 }
 
 

sql/opt_subselect.cc

@@ -531,7 +531,6 @@ static bool replace_where_subcondition(JOIN *join, Item **expr,
     *expr= new_cond;
     if (do_fix_fields)
       new_cond->fix_fields(join->thd, expr);
-    join->select_lex->where= *expr;
     return FALSE;
   }
   
@@ -3031,10 +3030,24 @@ int setup_semijoin_dups_elimination(JOIN *join, ulonglong options,
           forwards, but do not destroy other duplicate elimination methods.
         */
         uint first_table= i;
+        uint join_cache_level= join->thd->variables.join_cache_level;
         for (uint j= i; j < i + pos->n_sj_tables; j++)
         {
-          if (join->best_positions[j].use_join_buffer && j <= no_jbuf_after)
+          /*
+            When we'll properly take join buffering into account during
+            join optimization, the below check should be changed to 
+            "if (join->best_positions[j].use_join_buffer && 
+                 j <= no_jbuf_after)".
+            For now, use a rough criteria:
+          */
+          JOIN_TAB *js_tab=join->join_tab + j; 
+          if (j != join->const_tables && js_tab->use_quick != 2 &&
+              j <= no_jbuf_after &&
+              ((js_tab->type == JT_ALL && join_cache_level != 0) ||
+               (join_cache_level > 4 && (tab->type == JT_REF || 
+                                         tab->type == JT_EQ_REF))))
           {
+            /* Looks like we'll be using join buffer */
             first_table= join->const_tables;
             break;
           }
@@ -3112,7 +3125,12 @@ int setup_semijoin_dups_elimination(JOIN *join, ulonglong options,
         JOIN_TAB *j, *jump_to= tab-1;
         for (j= tab; j != tab + pos->n_sj_tables; j++)
         {
-          if (!tab->emb_sj_nest)
+          /*
+            NOTE: this loop probably doesn't do the right thing for the case 
+            where FirstMatch's duplicate-generating range is interleaved with
+            "unrelated" tables (as specified in WL#3750, section 2.2).
+          */
+          if (!j->emb_sj_nest)
             jump_to= tab;
           else
           {

sql/sql_join_cache.cc

@@ -31,6 +31,8 @@
 #include "sql_select.h"
 #include "opt_subselect.h"
 
+#define NO_MORE_RECORDS_IN_BUFFER  (uint)(-1)
+
 
 /*****************************************************************************
  *  Join cache module
@@ -408,7 +410,9 @@ void JOIN_CACHE::set_constants()
     the cache or not. Later when a referenced field is registered for the cache
     we adjust the value of the flag 'with_length'.
   */ 
-  with_length= is_key_access() || with_match_flag;
+  with_length= is_key_access() || 
+               join_tab->is_inner_table_of_semi_join_with_first_match() ||
+               join_tab->is_inner_table_of_outer_join();
   /* 
      At this moment we don't know yet the value of 'referenced_fields',
      but in any case it can't be greater than the value of 'fields'.
@@ -604,7 +608,12 @@ int JOIN_CACHE_BKA::init()
       copy_end= cache->field_descr+cache->fields;
       for (copy= cache->field_descr+cache->flag_fields; copy < copy_end; copy++)
       {
-        if (copy->field->table == tab->table &&
+        /*
+          (1) - when we store rowids for DuplicateWeedout, they have
+                copy->field==NULL
+        */
+        if (copy->field &&  // (1)
+            copy->field->table == tab->table &&
             bitmap_is_set(key_read_set, copy->field->field_index))
         {
           *copy_ptr++= copy; 
@@ -1235,7 +1244,7 @@ bool JOIN_CACHE::get_record()
     prev_rec_ptr= prev_cache->get_rec_ref(pos);
   }
   curr_rec_pos= pos;
-  if (!(res= read_all_record_fields() == 0))
+  if (!(res= read_all_record_fields() == NO_MORE_RECORDS_IN_BUFFER))
   {
     pos+= referenced_fields*size_of_fld_ofs;
     if (prev_cache)
@@ -1304,7 +1313,7 @@ bool JOIN_CACHE::get_match_flag_by_pos(uchar *rec_ptr)
     uchar *prev_rec_ptr= prev_cache->get_rec_ref(rec_ptr);
     return prev_cache->get_match_flag_by_pos(prev_rec_ptr);
   } 
-  DBUG_ASSERT(1);
+  DBUG_ASSERT(0);
   return FALSE;
 }
 
@@ -1324,7 +1333,8 @@ bool JOIN_CACHE::get_match_flag_by_pos(uchar *rec_ptr)
     read data. 
 
   RETURN
-    length of the data read from the join buffer
+    (-1) - if there is no more records in the join buffer
+    length of the data read from the join buffer - otherwise
 */
 
 uint JOIN_CACHE::read_all_record_fields()
@@ -1332,7 +1342,7 @@ uint JOIN_CACHE::read_all_record_fields()
   uchar *init_pos= pos;
   
   if (pos > last_rec_pos || !records)
-    return 0;
+    return NO_MORE_RECORDS_IN_BUFFER;
 
   /* First match flag, read null bitmaps and null_row flag for each table */
   read_flag_fields();
@@ -1538,12 +1548,12 @@ bool JOIN_CACHE::read_referenced_field(CACHE_FIELD *copy,
 
 bool JOIN_CACHE::skip_record_if_match()
 {
-  DBUG_ASSERT(with_match_flag && with_length);
+  DBUG_ASSERT(with_length);
   uint offset= size_of_rec_len;
   if (prev_cache)
     offset+= prev_cache->get_size_of_rec_offset();
   /* Check whether the match flag is on */
-  if (test(*(pos+offset)))
+  if (get_match_flag_by_pos(pos+offset))
   {
     pos+= size_of_rec_len + get_rec_length(pos);
     return TRUE;

sql/sql_select.cc

@@ -5636,6 +5636,10 @@ void calc_used_field_length(THD *thd, JOIN_TAB *join_tab)
 			     (join_tab->table->s->reclength-rec_length));
     rec_length+=(uint) max(4,blob_length);
   }  
+  /*
+    psergey-todo: why we don't count here rowid that we might need to store
+    when using DuplicateElimination?
+  */
   join_tab->used_fields=fields;
   join_tab->used_fieldlength=rec_length;
   join_tab->used_blobs=blobs;
@@ -6355,10 +6359,17 @@ make_outerjoin_info(JOIN *join)
       }
       if (!tab->first_inner)  
         tab->first_inner= nested_join->first_nested;
+      if (tab->table->reginfo.not_exists_optimize)
+        tab->first_inner->table->reginfo.not_exists_optimize= 1;         
       if (++nested_join->counter < nested_join->n_tables)
         break;
       /* Table tab is the last inner table for nested join. */
       nested_join->first_nested->last_inner= tab;
+      if (tab->first_inner->table->reginfo.not_exists_optimize)
+      {
+        for (JOIN_TAB *join_tab= tab->first_inner; join_tab <= tab; join_tab++)
+          join_tab->table->reginfo.not_exists_optimize= 1;
+      } 
     }
   }
   DBUG_VOID_RETURN;
@@ -7111,19 +7122,15 @@ uint check_join_cache_usage(JOIN_TAB *tab,
   */
   if (tab->use_quick == 2)
     goto no_join_cache;
-  /*
-    Use join cache with FirstMatch semi-join strategy only when semi-join
-    contains only one table.
-  */
-  if (tab->is_inner_table_of_semi_join_with_first_match() &&
-      !tab->is_single_inner_of_semi_join_with_first_match())
-    goto no_join_cache;
   /*
     Non-linked join buffers can't guarantee one match
   */
    if (force_unlinked_cache && 
+       (!tab->type == JT_ALL || cache_level <= 4) && 
+       ((tab->is_inner_table_of_semi_join_with_first_match() &&
+         !tab->is_single_inner_of_semi_join_with_first_match()) ||
         (tab->is_inner_table_of_outer_join() &&
-       !tab->is_single_inner_of_outer_join()))
+         !tab->is_single_inner_of_outer_join())))
     goto no_join_cache;
 
   /*

sql/sql_select.h

@@ -321,8 +321,8 @@ typedef struct st_join_table {
   }
   bool check_only_first_match()
   {
-    return  last_sj_inner_tab == this ||
-           (first_inner && first_inner->last_inner == this &&
+    return is_inner_table_of_semi_join_with_first_match() ||
+           (is_inner_table_of_outer_join() &&
             table->reginfo.not_exists_optimize);
   }
   bool is_last_inner_table()