MDEV-36133 BNL() hint doesn't work with join_cache_level>=5

This commit:
- fixes a couple of bugs in check_join_cache_usage();
- separates a part of opt_hints.test to a new file opt_hints_join_cache.test;
- add a batch of test cases run against different join_cache_level settings.

mysql-test/main/opt_hints.result

@@ -717,610 +717,7 @@ Handler_read_rnd	10
 Handler_read_rnd_deleted	0
 Handler_read_rnd_next	11
 DEALLOCATE PREPARE stmt1;
-DROP TABLE t1, t2, t3, t10, t11, t12, t13;
-#
-# BNL and NO_BNL hint testing
-#
-set optimizer_switch=default;
-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);
-# Check statistics without hint
-FLUSH STATUS;
-SELECT t1.* FROM t1,t2,t3;
-a	b
-1	1
-2	2
-1	1
-2	2
-1	1
-2	2
-1	1
-2	2
-SHOW STATUS LIKE 'handler_read%';
-Variable_name	Value
-Handler_read_first	0
-Handler_read_key	0
-Handler_read_last	0
-Handler_read_next	0
-Handler_read_prev	0
-Handler_read_retry	0
-Handler_read_rnd	0
-Handler_read_rnd_deleted	0
-Handler_read_rnd_next	9
-# Check statistics with hint
-FLUSH STATUS;
-SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
-a	b
-1	1
-1	1
-1	1
-1	1
-2	2
-2	2
-2	2
-2	2
-SHOW STATUS LIKE 'handler_read%';
-Variable_name	Value
-Handler_read_first	0
-Handler_read_key	0
-Handler_read_last	0
-Handler_read_next	0
-Handler_read_prev	0
-Handler_read_retry	0
-Handler_read_rnd	0
-Handler_read_rnd_deleted	0
-Handler_read_rnd_next	21
-EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-Warnings:
-Note	1003	select /*+ NO_BNL(@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ NO_BNL(t2, t3) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-Warnings:
-Note	1003	select /*+ NO_BNL(`t2`@`select#1`) NO_BNL(`t3`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ NO_BNL(t1, t3) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-Warnings:
-Note	1003	select /*+ NO_BNL(`t1`@`select#1`) NO_BNL(`t3`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-# Make sure query results are the same for any hints combination
-SELECT * FROM t1,t2,t3;
-a	b	a	b	a	b
-1	1	1	1	1	1
-1	1	1	1	2	2
-1	1	2	2	1	1
-1	1	2	2	2	2
-2	2	1	1	1	1
-2	2	1	1	2	2
-2	2	2	2	1	1
-2	2	2	2	2	2
-SELECT /*+ NO_BNL(t1, t2) */* FROM t1,t2,t3;
-a	b	a	b	a	b
-1	1	1	1	1	1
-1	1	1	1	2	2
-1	1	2	2	1	1
-1	1	2	2	2	2
-2	2	1	1	1	1
-2	2	1	1	2	2
-2	2	2	2	1	1
-2	2	2	2	2	2
-SELECT /*+ NO_BNL(t1, t3) */* FROM t1,t2,t3;
-a	b	a	b	a	b
-1	1	1	1	1	1
-1	1	1	1	2	2
-1	1	2	2	1	1
-1	1	2	2	2	2
-2	2	1	1	1	1
-2	2	1	1	2	2
-2	2	2	2	1	1
-2	2	2	2	2	2
-SELECT /*+ NO_BNL(t2, t3) */* FROM t1,t2,t3;
-a	b	a	b	a	b
-1	1	1	1	1	1
-1	1	1	1	2	2
-1	1	2	2	1	1
-1	1	2	2	2	2
-2	2	1	1	1	1
-2	2	1	1	2	2
-2	2	2	2	1	1
-2	2	2	2	2	2
-# BNL() overrides current join_cache_level setting
-set join_cache_level = 0;
-EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-Warnings:
-Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ BNL() */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ BNL(@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ BNL(t1, t2) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	
-Warnings:
-Note	1003	select /*+ BNL(`t1`@`select#1`) BNL(`t2`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ BNL(t1, t3) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-Warnings:
-Note	1003	select /*+ BNL(`t1`@`select#1`) BNL(`t3`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ BNL(t2, t3) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ BNL(`t2`@`select#1`) BNL(`t3`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-EXPLAIN EXTENDED SELECT /*+ BNL(t2) BNL(t3) */t1.* FROM t1,t2,t3;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ BNL(`t2`@`select#1`) BNL(`t3`@`select#1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` join `test`.`t2` join `test`.`t3`
-DROP TABLE t1, t2, t3;
-set join_cache_level = 8;
-# BNL in subquery
-set optimizer_switch = DEFAULT;
-CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a));
-CREATE TABLE t2 (a INT);
-CREATE TABLE t3 (a INT, b INT, INDEX a (a,b));
-INSERT INTO t1 VALUES (1,10), (2,20), (3,30), (4,40);
-INSERT INTO t2 VALUES (2), (3), (4), (5);
-INSERT INTO t3 VALUES (10,3), (20,4), (30,5);
-ANALYZE TABLE t1, t2, t3;
-Table	Op	Msg_type	Msg_text
-test.t1	analyze	status	Engine-independent statistics collected
-test.t1	analyze	status	OK
-test.t2	analyze	status	Engine-independent statistics collected
-test.t2	analyze	status	OK
-test.t3	analyze	status	Engine-independent statistics collected
-test.t3	analyze	status	OK
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index; Using join buffer (incremental, BNL join)
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2); Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL() */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	4	10.00	Using where
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index; Using join buffer (flat, BNL join)
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2); Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(@`q`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	4	10.00	Using where
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index; Using join buffer (flat, BNL join)
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2); Using join buffer (incremental, BNL join)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(`t1`@`q`) NO_BNL(`t2`@`q`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(@`subq1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(`t4`@`subq1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(`t3`@`subq1`) NO_BNL(`t4`@`subq1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(`t3`@`subq1`) NO_BNL(`t4`@`subq1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
-FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	4	100.00	
-1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	10.00	Using where; Using join buffer (flat, BNLH join)
-1	PRIMARY	t3	index	a	a	10	NULL	3	10.00	Using where; Using index
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	4	25.00	Using where; FirstMatch(t2)
-Warnings:
-Note	1003	select /*+ QB_NAME(`q`) NO_BNL(`t3`@`subq1`) NO_BNL(`t4`@`subq1`) */ `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`a` AS `a` from `test`.`t1` semi join (`test`.`t3` join `test`.`t1` `t4`) join `test`.`t2` where `test`.`t2`.`a` = `test`.`t1`.`a` and `test`.`t3`.`b` = `test`.`t1`.`a` and `test`.`t4`.`b` = `test`.`t3`.`a`
-# Make sure query results are the same for any hints combination
-SELECT * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL() */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-SELECT /*+ QB_NAME(q) */ *
-FROM t1 JOIN t2 ON t1.a = t2.a
-WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
-FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-a	b	a
-3	30	3
-4	40	4
-DROP TABLE t1, t2, t3, t4;
-#
-# BNL() and NO_BNL() for LEFT JOINs
-#
-CREATE TABLE t1 (a int);
-CREATE TABLE t2 (a int);
-CREATE TABLE t3 (a int);
-CREATE TABLE t4 (a int);
-INSERT INTO t1 VALUES (null), (2), (null), (1);
-set join_cache_level = 8;
-# Two join buffers are employed by default (without hints):
-EXPLAIN SELECT t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-WHERE t1.a OR t3.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (incremental, BNL join)
-# Disabling either of join buffers disables another one automatically due
-# to join buffer employment rules:
-EXPLAIN SELECT /*+ NO_BNL(t2) */ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-WHERE t1.a OR t3.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-EXPLAIN SELECT /*+ NO_BNL(t3) */ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-WHERE t1.a OR t3.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-# Three join buffers are employed here by default (without hints):
-EXPLAIN SELECT t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (incremental, BNL join)
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (incremental, BNL join)
-# Disabling either of join buffers disables others automatically due
-# to join buffer employment rules:
-EXPLAIN SELECT /*+ NO_BNL(t2)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where
-EXPLAIN SELECT /*+ NO_BNL(t3)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where
-EXPLAIN SELECT /*+ NO_BNL(t4)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where
-set join_cache_level=0;
-# It is not allowed to enable join buffers on some subset of inner tables
-# of an outer join. Either all tables should use join buffers or none:
-EXPLAIN SELECT /*+ BNL(t2)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where
-EXPLAIN SELECT /*+ BNL(t2, t3)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where
-EXPLAIN SELECT /*+ BNL(t2, t3, t4)*/ t1.a
-FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-WHERE t1.a OR t4.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (incremental, BNL join)
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	0	Using where; Using join buffer (incremental, BNL join)
-set join_cache_level=8;
-INSERT INTO t2 VALUES (1), (2), (null), (1);
-# BNLH buffer is used when allowed by JCL setting
-EXPLAIN SELECT * FROM t1, t2 WHERE t1.a=t2.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
-1	SIMPLE	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	Using where; Using join buffer (flat, BNLH join)
-# Make sure the hint enables BNL even when JCL=0:
-set join_cache_level=0;
-EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
-1	SIMPLE	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	Using where; Using join buffer (flat, BNLH join)
-set join_cache_level=2;
-EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
-1	SIMPLE	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	4	Using where; Using join buffer (flat, BNLH join)
-DROP TABLE t1,t2,t3,t4;
-#
-# Mix of BNL/BKA flat and incremental join buffers for OUTER JOINs
-#
-set optimizer_switch='outer_join_with_cache=on,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
-CREATE TABLE t1 (a1 varchar(32)) ;
-INSERT INTO t1 VALUES ('s'),('k');
-CREATE TABLE t2 (a2 int PRIMARY KEY, b2 varchar(32)) ;
-INSERT INTO t2 VALUES (7,'s');
-CREATE TABLE t3 (a3 int PRIMARY KEY, b3 varchar(32)) ;
-INSERT INTO t3 VALUES (7,'s');
-CREATE TABLE t4 (a4 int);
-INSERT INTO t4 VALUES (9);
-CREATE TABLE t5(a5 int PRIMARY KEY, b5 int) ;
-INSERT INTO t5 VALUES (7,0);
-ANALYZE TABLES t1, t2, t3, t4, t5;
-# Disable join buffering to enable it selectively on particular tables
-SET SESSION join_cache_level = 0;
-EXPLAIN
-SELECT t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	1	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t3.a3	1	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where
-SELECT t4.a4, t5.b5 
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-EXPLAIN
-SELECT /*+ BNL(t4) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	1	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t3.a3	1	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where
-SELECT /*+ BNL(t4) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	1	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t3.a3	1	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	hash_ALL	PRIMARY	#hash#PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BNLH join)
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-# BNL() hint overrides join_cache_levels from 0 to 3 increasing it to 4
-set join_cache_level = 1;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	1	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t3.a3	1	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	hash_ALL	PRIMARY	#hash#PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BNLH join)
-set join_cache_level = 2;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t3	index	PRIMARY	PRIMARY	4	NULL	1	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t3.a3	1	Using where
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	hash_ALL	PRIMARY	#hash#PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BNLH join)
-set join_cache_level = 3;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-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	PRIMARY	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	hash_ALL	PRIMARY	#hash#PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BNLH join)
-# Enable all join buffering capabilities:
-SET SESSION join_cache_level = 8;
-EXPLAIN
-SELECT t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-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	PRIMARY	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BKAH join); Key-ordered Rowid-ordered scan
-SELECT t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-EXPLAIN
-SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-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	PRIMARY	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (flat, BKAH join); Key-ordered Rowid-ordered scan
-SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-# Disable BKA so the BNLH join buffer will be employed:
-EXPLAIN
-SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-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	PRIMARY	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	hash_ALL	PRIMARY	#hash#PRIMARY	4	test.t2.a2	1	Using where; Using join buffer (incremental, BNLH join)
-SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-EXPLAIN
-SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-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	PRIMARY	NULL	NULL	NULL	1	Using where
-1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using index
-1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t2.a2	1	Using where
-SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
-FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-a4	b5
-9	0
-9	NULL
-DROP TABLE t1,t2,t3,t4,t5;
+DROP TABLE t1, t2, t3, t4, t10, t11, t12, t13;
 # MRR & NO_MRR hint testing
 set optimizer_switch=default;
 set join_cache_level = 8;

mysql-test/main/opt_hints.test

@@ -378,322 +378,7 @@ SHOW STATUS LIKE 'handler_read%';
 
 DEALLOCATE PREPARE stmt1;
 
-DROP TABLE t1, t2, t3, t10, t11, t12, t13;
-
---echo #
---echo # BNL and NO_BNL hint testing
---echo #
-
-set optimizer_switch=default;
-
-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);
-
---disable_ps2_protocol
---disable_cursor_protocol
---echo # Check statistics without hint
-FLUSH STATUS;
-SELECT t1.* FROM t1,t2,t3;
-SHOW STATUS LIKE 'handler_read%';
-
---echo # Check statistics with hint
-FLUSH STATUS;
-SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
-SHOW STATUS LIKE 'handler_read%';
---enable_ps2_protocol
---enable_cursor_protocol
-
-EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ NO_BNL(t2, t3) */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ NO_BNL(t1, t3) */t1.* FROM t1,t2,t3;
-
---echo # Make sure query results are the same for any hints combination
---sorted_result
-SELECT * FROM t1,t2,t3;
---sorted_result
-SELECT /*+ NO_BNL(t1, t2) */* FROM t1,t2,t3;
---sorted_result
-SELECT /*+ NO_BNL(t1, t3) */* FROM t1,t2,t3;
---sorted_result
-SELECT /*+ NO_BNL(t2, t3) */* FROM t1,t2,t3;
-
---echo # BNL() overrides current join_cache_level setting
-set join_cache_level = 0;
-EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ BNL() */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ BNL(t1, t2) */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ BNL(t1, t3) */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ BNL(t2, t3) */t1.* FROM t1,t2,t3;
-EXPLAIN EXTENDED SELECT /*+ BNL(t2) BNL(t3) */t1.* FROM t1,t2,t3;
-
-DROP TABLE t1, t2, t3;
-set join_cache_level = 8;
-
---echo # BNL in subquery
-set optimizer_switch = DEFAULT;
-CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a));
-CREATE TABLE t2 (a INT);
-CREATE TABLE t3 (a INT, b INT, INDEX a (a,b));
-INSERT INTO t1 VALUES (1,10), (2,20), (3,30), (4,40);
-INSERT INTO t2 VALUES (2), (3), (4), (5);
-INSERT INTO t3 VALUES (10,3), (20,4), (30,5);
-ANALYZE TABLE t1, t2, t3;
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL() */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
-    FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
---echo # Make sure query results are the same for any hints combination
-# --sorted_result
-SELECT * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-# --sorted_result
-SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
-t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL() */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
---sorted_result
-SELECT /*+ QB_NAME(q) */ *
-  FROM t1 JOIN t2 ON t1.a = t2.a
-  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
-    FROM t3 JOIN t1 t4 ON t3.a = t4.b);
-
-DROP TABLE t1, t2, t3, t4;
-
---echo #
---echo # BNL() and NO_BNL() for LEFT JOINs
---echo #
-
-CREATE TABLE t1 (a int);
-CREATE TABLE t2 (a int);
-CREATE TABLE t3 (a int);
-CREATE TABLE t4 (a int);
-
-INSERT INTO t1 VALUES (null), (2), (null), (1);
-
-set join_cache_level = 8;
-
---echo # Two join buffers are employed by default (without hints):
-EXPLAIN SELECT t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-    WHERE t1.a OR t3.a;
-
---echo # Disabling either of join buffers disables another one automatically due
---echo # to join buffer employment rules:
-EXPLAIN SELECT /*+ NO_BNL(t2) */ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-    WHERE t1.a OR t3.a;
-
-EXPLAIN SELECT /*+ NO_BNL(t3) */ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
-    WHERE t1.a OR t3.a;
-
---echo # Three join buffers are employed here by default (without hints):
-EXPLAIN SELECT t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-
---echo # Disabling either of join buffers disables others automatically due
---echo # to join buffer employment rules:
-EXPLAIN SELECT /*+ NO_BNL(t2)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-EXPLAIN SELECT /*+ NO_BNL(t3)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-EXPLAIN SELECT /*+ NO_BNL(t4)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-
-set join_cache_level=0;
---echo # It is not allowed to enable join buffers on some subset of inner tables
---echo # of an outer join. Either all tables should use join buffers or none:
-EXPLAIN SELECT /*+ BNL(t2)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-EXPLAIN SELECT /*+ BNL(t2, t3)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-EXPLAIN SELECT /*+ BNL(t2, t3, t4)*/ t1.a
-  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
-    WHERE t1.a OR t4.a;
-
-set join_cache_level=8;
-INSERT INTO t2 VALUES (1), (2), (null), (1);
---echo # BNLH buffer is used when allowed by JCL setting
-EXPLAIN SELECT * FROM t1, t2 WHERE t1.a=t2.a;
-
---echo # Make sure the hint enables BNL even when JCL=0:
-set join_cache_level=0;
-EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
-
-set join_cache_level=2;
-EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
-
-DROP TABLE t1,t2,t3,t4;
-
-
---echo #
---echo # Mix of BNL/BKA flat and incremental join buffers for OUTER JOINs
---echo #
-
-set optimizer_switch='outer_join_with_cache=on,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
-
-CREATE TABLE t1 (a1 varchar(32)) ;
-INSERT INTO t1 VALUES ('s'),('k');
-
-CREATE TABLE t2 (a2 int PRIMARY KEY, b2 varchar(32)) ;
-INSERT INTO t2 VALUES (7,'s');
-
-CREATE TABLE t3 (a3 int PRIMARY KEY, b3 varchar(32)) ;
-INSERT INTO t3 VALUES (7,'s');
-
-CREATE TABLE t4 (a4 int);
-INSERT INTO t4 VALUES (9);
-
-CREATE TABLE t5(a5 int PRIMARY KEY, b5 int) ;
-INSERT INTO t5 VALUES (7,0);
---disable_result_log
-ANALYZE TABLES t1, t2, t3, t4, t5;
---enable_result_log
-
---echo # Disable join buffering to enable it selectively on particular tables
-SET SESSION join_cache_level = 0;
-EXPLAIN
-SELECT t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT t4.a4, t5.b5 
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-EXPLAIN
-SELECT /*+ BNL(t4) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT /*+ BNL(t4) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
---echo # BNL() hint overrides join_cache_levels from 0 to 3 increasing it to 4
-set join_cache_level = 1;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-set join_cache_level = 2;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-set join_cache_level = 3;
-EXPLAIN
-SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
---echo # Enable all join buffering capabilities:
-SET SESSION join_cache_level = 8;
-EXPLAIN
-SELECT t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-EXPLAIN
-SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
---echo # Disable BKA so the BNLH join buffer will be employed:
-EXPLAIN
-SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-EXPLAIN
-SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
-  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
-       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
-
-DROP TABLE t1,t2,t3,t4,t5;
-
+DROP TABLE t1, t2, t3, t4, t10, t11, t12, t13;
 
 --echo # MRR & NO_MRR hint testing
 set optimizer_switch=default;

mysql-test/main/opt_hints_join_cache.inc

@@ -0,0 +1,18 @@
+EXPLAIN  SELECT * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+--echo --------------------------------------------
+EXPLAIN  SELECT /*+ BKA() */ * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+--echo --------------------------------------------
+EXPLAIN  SELECT /*+ BNL() */ * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+--echo --------------------------------------------
+EXPLAIN  SELECT /*+ NO_BKA() */ * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+--echo --------------------------------------------
+EXPLAIN  SELECT /*+ NO_BNL() */ * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+--echo --------------------------------------------
+EXPLAIN  SELECT /*+ NO_BKA() NO_BNL() */ * FROM t12, t13
+  WHERE t12.a=t13.a AND (t13.b+1 <= t12.b+1);
+

mysql-test/main/opt_hints_join_cache.test

@@ -0,0 +1,528 @@
+set @tmp_jcl= @@join_cache_level;
+set @tmp_opt= @@optimizer_switch;
+
+CREATE TABLE t10(a INT);
+INSERT INTO t10 VALUES (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+CREATE TABLE t12(a INT, b INT);
+INSERT INTO t12 SELECT a,a from t10;
+CREATE TABLE t13(a INT, b INT, c INT, filler CHAR(100), key (a,b));
+INSERT INTO t13 select a,a,a, 'filler-data' FROM t10;
+
+--echo
+--echo ================================================================
+set optimizer_switch= 'join_cache_hashed=on,join_cache_bka=on,mrr=on';
+
+--echo
+--echo ***********************************************
+set join_cache_level = 0;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 1;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 2;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 3;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 4;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 5;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 6;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 7;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 8;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ================================================================
+set optimizer_switch= 'join_cache_hashed=off,join_cache_bka=on,mrr=on';
+
+--echo
+--echo ***********************************************
+set join_cache_level = 0;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 1;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 2;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 3;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 4;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 5;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 6;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 7;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 8;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ================================================================
+set optimizer_switch= 'join_cache_hashed=on,join_cache_bka=off,mrr=on';
+
+--echo
+--echo ***********************************************
+set join_cache_level = 0;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 1;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 2;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 3;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 4;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 5;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 6;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 7;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 8;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ================================================================
+set optimizer_switch= 'join_cache_hashed=off,join_cache_bka=off,mrr=on';
+
+--echo
+--echo ***********************************************
+set join_cache_level = 0;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 1;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 2;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 3;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 4;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 5;
+--source opt_hints_join_cache.inc
+
+set join_cache_level = 6;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 7;
+--source opt_hints_join_cache.inc
+
+--echo
+--echo ***********************************************
+set join_cache_level = 8;
+--source opt_hints_join_cache.inc
+
+drop tables t10, t12, t13;
+
+--echo
+--echo ================================================================
+set optimizer_switch= 'join_cache_hashed=on,join_cache_bka=on,mrr=on';
+
+--echo #
+--echo # BNL and NO_BNL hint testing
+--echo #
+
+set optimizer_switch=default;
+
+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);
+
+--disable_ps2_protocol
+--disable_cursor_protocol
+--echo # Check statistics without hint
+FLUSH STATUS;
+SELECT t1.* FROM t1,t2,t3;
+SHOW STATUS LIKE 'handler_read%';
+
+--echo # Check statistics with hint
+FLUSH STATUS;
+SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
+SHOW STATUS LIKE 'handler_read%';
+--enable_ps2_protocol
+--enable_cursor_protocol
+
+EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ NO_BNL() */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ NO_BNL(t2, t3) */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ NO_BNL(t1, t3) */t1.* FROM t1,t2,t3;
+
+--echo # Make sure query results are the same for any hints combination
+--sorted_result
+SELECT * FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ BNL() */t1.* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ BNL(t1, t2) */t1.* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ BNL(t1, t3) */t1.* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ BNL(t2, t3) */t1.* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ BNL(t2) BNL(t3) */t1.* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ NO_BNL() */* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ NO_BNL(t1, t2) */* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ NO_BNL(t1, t3) */* FROM t1,t2,t3;
+--sorted_result
+SELECT /*+ NO_BNL(t2, t3) */* FROM t1,t2,t3;
+
+--echo # BNL() overrides current join_cache_level setting
+set join_cache_level = 0;
+EXPLAIN EXTENDED SELECT t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ BNL() */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ BNL(t1, t2) */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ BNL(t1, t3) */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ BNL(t2, t3) */t1.* FROM t1,t2,t3;
+EXPLAIN EXTENDED SELECT /*+ BNL(t2) BNL(t3) */t1.* FROM t1,t2,t3;
+
+DROP TABLE t1, t2, t3;
+set join_cache_level = 8;
+
+--echo # BNL in subquery
+set optimizer_switch = DEFAULT;
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a));
+CREATE TABLE t2 (a INT);
+CREATE TABLE t3 (a INT, b INT, INDEX a (a,b));
+INSERT INTO t1 VALUES (1,10), (2,20), (3,30), (4,40);
+INSERT INTO t2 VALUES (2), (3), (4), (5);
+INSERT INTO t3 VALUES (10,3), (20,4), (30,5);
+ANALYZE TABLE t1, t2, t3;
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
+t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL() */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+EXPLAIN EXTENDED SELECT /*+ QB_NAME(q) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
+    FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+--echo # Make sure query results are the same for any hints combination
+# --sorted_result
+SELECT * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
+t2.a IN (SELECT t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+# --sorted_result
+SELECT /*+ QB_NAME(q) */ * FROM t1 JOIN t2 ON t1.a = t2.a WHERE
+t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL() */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL(t1, t2) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL(@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL(t4@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL(t3@subq1,t4@subq1) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) NO_BNL(@subq1 t3, t4) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1) */ t3.b FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+--sorted_result
+SELECT /*+ QB_NAME(q) */ *
+  FROM t1 JOIN t2 ON t1.a = t2.a
+  WHERE t2.a IN (SELECT /*+ QB_NAME(subq1)  NO_BNL(t3, t4) */ t3.b
+    FROM t3 JOIN t1 t4 ON t3.a = t4.b);
+
+DROP TABLE t1, t2, t3;
+
+--echo #
+--echo # BNL() and NO_BNL() for LEFT JOINs
+--echo #
+
+CREATE TABLE t1 (a int);
+CREATE TABLE t2 (a int);
+CREATE TABLE t3 (a int);
+CREATE TABLE t4 (a int);
+
+INSERT INTO t1 VALUES (null), (2), (null), (1);
+
+set join_cache_level = 8;
+
+--echo # Two join buffers are employed by default (without hints):
+EXPLAIN SELECT t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
+    WHERE t1.a OR t3.a;
+
+--echo # Disabling either of join buffers disables another one automatically due
+--echo # to join buffer employment rules:
+EXPLAIN SELECT /*+ NO_BNL(t2) */ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
+    WHERE t1.a OR t3.a;
+
+EXPLAIN SELECT /*+ NO_BNL(t3) */ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN t3 ON t2.a) ON 0
+    WHERE t1.a OR t3.a;
+
+--echo # Three join buffers are employed here by default (without hints):
+EXPLAIN SELECT t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+
+--echo # Disabling either of join buffers disables others automatically due
+--echo # to join buffer employment rules:
+EXPLAIN SELECT /*+ NO_BNL(t2)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+EXPLAIN SELECT /*+ NO_BNL(t3)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+EXPLAIN SELECT /*+ NO_BNL(t4)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+
+set join_cache_level=0;
+--echo # It is not allowed to enable join buffers on some subset of inner tables
+--echo # of an outer join. Either all tables should use join buffers or none:
+EXPLAIN SELECT /*+ BNL(t2)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+EXPLAIN SELECT /*+ BNL(t2, t3)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+EXPLAIN SELECT /*+ BNL(t2, t3, t4)*/ t1.a
+  FROM t1 LEFT JOIN (t2 LEFT JOIN (t3 LEFT JOIN t4 ON 1) ON t2.a) ON 0
+    WHERE t1.a OR t4.a;
+
+set join_cache_level=8;
+INSERT INTO t2 VALUES (1), (2), (null), (1);
+--echo # BNLH buffer is used when allowed by JCL setting
+EXPLAIN SELECT * FROM t1, t2 WHERE t1.a=t2.a;
+
+--echo # Make sure the hint enables BNL even when JCL=0:
+set join_cache_level=0;
+EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
+
+set join_cache_level=2;
+EXPLAIN SELECT /*+BNL(t2) */ * FROM t1, t2 WHERE t1.a=t2.a;
+
+DROP TABLE t1,t2,t3,t4;
+
+
+--echo #
+--echo # Mix of BNL/BKA flat and incremental join buffers for OUTER JOINs
+--echo #
+
+set optimizer_switch='outer_join_with_cache=on,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
+
+CREATE TABLE t1 (a1 varchar(32)) ;
+INSERT INTO t1 VALUES ('s'),('k');
+
+CREATE TABLE t2 (a2 int PRIMARY KEY, b2 varchar(32)) ;
+INSERT INTO t2 VALUES (7,'s');
+
+CREATE TABLE t3 (a3 int PRIMARY KEY, b3 varchar(32)) ;
+INSERT INTO t3 VALUES (7,'s');
+
+CREATE TABLE t4 (a4 int);
+INSERT INTO t4 VALUES (9);
+
+CREATE TABLE t5(a5 int PRIMARY KEY, b5 int) ;
+INSERT INTO t5 VALUES (7,0);
+--disable_result_log
+ANALYZE TABLES t1, t2, t3, t4, t5;
+--enable_result_log
+
+--echo # Disable join buffering to enable it selectively on particular tables
+SET SESSION join_cache_level = 0;
+EXPLAIN
+SELECT t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT t4.a4, t5.b5 
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+EXPLAIN
+SELECT /*+ BNL(t4) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT /*+ BNL(t4) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+EXPLAIN
+SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+--echo # BNL() hint overrides join_cache_levels from 0 to 3 increasing it to 4
+set join_cache_level = 1;
+EXPLAIN
+SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+set join_cache_level = 2;
+EXPLAIN
+SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+set join_cache_level = 3;
+EXPLAIN
+SELECT /*+ BNL(t4, t5) */ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+--echo # Enable all join buffering capabilities:
+SET SESSION join_cache_level = 8;
+EXPLAIN
+SELECT t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+EXPLAIN
+SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT /*+ NO_BNL(t4)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+--echo # Disable BKA so the BNLH join buffer will be employed:
+EXPLAIN
+SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT /*+ NO_BKA(t5)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+EXPLAIN
+SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+SELECT /*+ NO_BKA(t5) NO_BNL(t5)*/ t4.a4, t5.b5
+  FROM ((t1 LEFT JOIN (t2 JOIN t3 ON t2.a2 = t3.a3) ON t2.b2 = t1.a1)
+       LEFT JOIN t4 ON t4.a4 <> 0) LEFT JOIN t5 ON t5.a5 = t2.a2;
+
+DROP TABLE t1,t2,t3,t4,t5;
+
+set @@join_cache_level= @tmp_jcl;
+set @@optimizer_switch= @tmp_opt;

sql/sql_select.cc

@@ -15790,6 +15790,8 @@ uint check_join_cache_usage(JOIN_TAB *tab,
                                             BNL_HINT_ENUM, true);
   bool no_bka_cache= !hint_table_state(join->thd, tab->tab_list->table,
           BKA_HINT_ENUM, join->allowed_join_cache_types & JOIN_CACHE_BKA_BIT);
+  bool hint_forces_bnl= hint_table_state(join->thd, tab->tab_list->table,
+                                         BNL_HINT_ENUM, false);
   bool hint_forces_bka= hint_table_state(join->thd, tab->tab_list->table,
                                          BKA_HINT_ENUM, false);
   join->return_tab= 0;
@@ -15797,18 +15799,30 @@ uint check_join_cache_usage(JOIN_TAB *tab,
   if (tab->no_forced_join_cache || (hint_disables_bnl && no_bka_cache))
     goto no_join_cache;
 
-  if (cache_level < 4 && hint_table_state(join->thd, tab->tab_list->table,
-                                          BNL_HINT_ENUM, false))
+  // Hints BNL() and BKA() cannot be both specified for a single table
+  DBUG_ASSERT(!(hint_forces_bnl && hint_forces_bka));
+
+  if (cache_level < 4 && hint_forces_bnl)
+  {
+    // BNL() hint present, raise join_cache_level to BNLH-incremental
+    cache_level= 4;
+  }
+  else if (hint_forces_bka && !(cache_level >= 5 && cache_level <= 8))
   {
-    cache_level= 4; // BNL() hint present, raise join_cache_level to BNLH
+    /*
+      BKA() hint present. If join_cache_level is already set to BKA or BKAH,
+      just ignore the hint. For other join_cache_levels raise the level to
+      maximum possible (BKAH incremental) as there is no such granularity
+      in hints as there is in join cache levels
+    */
+    cache_level= 8;
   }
 
   /*
-    Don't use join cache if @@join_cache_level==0 and hint BKA()
-    is not specified or this table is the first
+    Don't use join cache if @@join_cache_level==0 or this table is the first
     one join suborder (either at top level or inside a bush)
   */
-  if ((cache_level == 0 && !hint_forces_bka) || !prev_tab)
+  if (cache_level == 0 || !prev_tab)
   {
     /*
       We could have cache_level==0 but join cache was forced for some previous
@@ -15955,10 +15969,9 @@ uint check_join_cache_usage(JOIN_TAB *tab,
   case JT_CONST:
   case JT_REF:
   case JT_EQ_REF:
-    if (hint_forces_bka)
-      cache_level= 8; // Increase to BKAH incremental
     if (cache_level <=2 || (no_hashed_cache && no_bka_cache))
       goto no_join_cache;
+
     if (tab->ref.is_access_triggered())
       goto no_join_cache;
 
@@ -15976,8 +15989,10 @@ uint check_join_cache_usage(JOIN_TAB *tab,
 
     if ((cache_level <=4 && !no_hashed_cache) || no_bka_cache ||
         tab->is_ref_for_hash_join() ||
-	((flags & HA_MRR_NO_ASSOCIATION) && cache_level <=6))
+        ((flags & HA_MRR_NO_ASSOCIATION) && cache_level <=6) ||
+        (hint_forces_bnl && !no_hashed_cache))
     {
+      // Only BNLH cache is applicable for the conditions given
       if (hint_disables_bnl)
         goto no_join_cache;
       if (!tab->hash_join_is_possible() ||
@@ -15992,11 +16007,13 @@ uint check_join_cache_usage(JOIN_TAB *tab,
       }
       goto no_join_cache;
     }
+
+    // Check and apply BKA/BKAH cache if possible
     if (cache_level < 5 || no_bka_cache)
       goto no_join_cache;
-    
+
     if ((flags & HA_MRR_NO_ASSOCIATION) &&
-	(cache_level <= 6 || no_hashed_cache))
+       (cache_level <= 6 || no_hashed_cache))
       goto no_join_cache;
 
     if ((rows != HA_POS_ERROR) && !(flags & HA_MRR_USE_DEFAULT_IMPL))