The patch adds the code that allows to use equi-join conditions

for hash join in the cases when there are no suitable indexes
for these conditions.

mysql-test/r/join_outer_jcl6.result

@@ -319,11 +319,11 @@ Lilliana Angelovska	NULL	NULL
 explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.id is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Not exists; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	2	test.t1.id	3	Using where; Not exists; Using join buffer (flat, BNLH join)
 explain select t1.name, t2.name, t2.id from t1 left join t2 on (t1.id = t2.owner) where t2.name is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	2	test.t1.id	3	Using where; Using join buffer (flat, BNLH join)
 select count(*) from t1 left join t2 on (t1.id = t2.owner);
 count(*)
 4
@@ -339,11 +339,11 @@ Lilliana Angelovska	NULL	NULL
 explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.id is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Not exists; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	2	test.t1.id	3	Using where; Not exists; Using join buffer (flat, BNLH join)
 explain select t1.name, t2.name, t2.id from t2 right join t1 on (t1.id = t2.owner) where t2.name is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	2	test.t1.id	3	Using where; Using join buffer (flat, BNLH join)
 select count(*) from t2 right join t1 on (t1.id = t2.owner);
 count(*)
 4
@@ -695,8 +695,8 @@ a1	a2	b1	b2	c1	c2
 explain select * from t1 left join t2  on  b1 = a1 left join t3  on  c1 = a1  and  b1 is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (incremental, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	4	test.t1.a1	2	Using where; Using join buffer (flat, BNLH join)
+1	SIMPLE	t3	hash	NULL	hj_key	5	test.t1.a1	2	Using where; Using join buffer (incremental, BNLH join)
 drop table t1, t2, t3;
 create table t1 (
 a int(11),

mysql-test/r/select_jcl6.result

@@ -1370,7 +1370,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain select t2.companynr,companyname from t4 left join t2 using (companynr) where t2.companynr is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1200	Using where; Not exists; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1200	Using where; Not exists; Using join buffer (flat, BNLH join)
 select companynr,companyname from t2 left join t4 using (companynr) where companynr is null;
 companynr	companyname
 select count(*) from t2 left join t4 using (companynr) where companynr is not null;
@@ -1398,39 +1398,39 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain select companynr,companyname from t4 left join t2 using (companynr) where companynr > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select companynr,companyname from t4 left join t2 using (companynr) where companynr > 0 or companynr < 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select companynr,companyname from t4 left join t2 using (companynr) where companynr > 0 and companynr > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select t2.companynr,companyname from t4 left join t2 using (companynr) where t2.companynr > 0 or t2.companynr is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select t2.companynr,companyname from t4 left join t2 using (companynr) where t2.companynr > 0 or t2.companynr < 0 or t4.companynr > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select t2.companynr,companyname from t4 left join t2 using (companynr) where ifnull(t2.companynr,1)>0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select companynr,companyname from t4 left join t2 using (companynr) where companynr > 0 or companynr is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select companynr,companyname from t4 left join t2 using (companynr) where companynr > 0 or companynr < 0 or companynr > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	PRIMARY	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 explain select companynr,companyname from t4 left join t2 using (companynr) where ifnull(companynr,1)>0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	test.t4.companynr	1199	Using where; Using join buffer (flat, BNLH join)
 select distinct t2.companynr,t4.companynr from t2,t4 where t2.companynr=t4.companynr+1;
 companynr	companynr
 37	36
@@ -1438,7 +1438,7 @@ companynr	companynr
 explain select distinct t2.companynr,t4.companynr from t2,t4 where t2.companynr=t4.companynr+1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t4	index	NULL	PRIMARY	1	NULL	12	Using index; Using temporary
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1199	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	1	func	1199	Using where; Using join buffer (flat, BNLH join)
 select t2.fld1,t2.companynr,fld3,period from t3,t2 where t2.fld1 = 38208 and t2.fld1=t3.t2nr and period = 1008 or t2.fld1 = 38008 and t2.fld1 =t3.t2nr and period = 1008;
 fld1	companynr	fld3	period
 038008	37	reporters	1008
@@ -2337,7 +2337,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t3	system	NULL	NULL	NULL	NULL	0	const row not found
 1	SIMPLE	t4	const	id4	NULL	NULL	NULL	1	
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	hash	NULL	hj_key	4	test.t1.id1	1	Using where; Using join buffer (flat, BNLH join)
 select * from t1 left join t2 on id1 = id2 left join t3 on id1 = id3
 left join t4 on id3 = id4 where id2 = 1 or id4 = 1;
 id1	id2	id3	id4	id44
@@ -2916,12 +2916,12 @@ a
 4
 EXPLAIN SELECT t1.a FROM t1 STRAIGHT_JOIN t2 ON 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	5	
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	Using where
+1	SIMPLE	t2	hash	NULL	hj_key	5	test.t1.a	3	Using where; Using join buffer (flat, BNLH join)
 EXPLAIN SELECT t1.a FROM t1 INNER JOIN t2 ON t1.a=t2.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	SIMPLE	t1	hash	NULL	hj_key	5	test.t2.a	5	Using where; Using join buffer (flat, BNLH join)
 DROP TABLE t1,t2;
 select x'10' + 0, X'10' + 0, b'10' + 0, B'10' + 0;
 x'10' + 0	X'10' + 0	b'10' + 0	B'10' + 0

mysql-test/r/subselect3_jcl6.result

@@ -1031,10 +1031,10 @@ explain select t21.* from t21,t22 where t21.a = t22.a and
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	8	Using temporary; Using filesort
-1	PRIMARY	t21	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t22	ALL	NULL	NULL	NULL	NULL	26	Using where; Using join buffer (incremental, BNL join)
+1	PRIMARY	t21	hash	NULL	hj_key	4	test.t11.a	26	Using where; Using join buffer (flat, BNLH join)
+1	PRIMARY	t22	hash	NULL	hj_key	4	test.t21.a	26	Using where; Using join buffer (incremental, BNLH join)
 2	SUBQUERY	t11	ALL	NULL	NULL	NULL	NULL	8	Using where
-2	SUBQUERY	t12	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	t12	hash	NULL	hj_key	4	test.t11.a	8	Using where; Using join buffer (flat, BNLH join)
 select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 a	b	c
@@ -1151,11 +1151,11 @@ set @@optimizer_switch='firstmatch=off,materialization=off';
 set @@max_heap_table_size= 16384;
 explain select count(*) from t0 A, t0 B, t0 C, t0 D where D.a in (select a from t1 E);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	E	ALL	NULL	NULL	NULL	NULL	5	Start temporary
+1	PRIMARY	E	ALL	NULL	NULL	NULL	NULL	5	Using where; Start temporary
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (incremental, BNL join)
 1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (incremental, BNL join)
-1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	10	Using where; End temporary; Using join buffer (incremental, BNL join)
+1	PRIMARY	D	hash	NULL	hj_key	5	test.E.a	10	Using where; End temporary; Using join buffer (incremental, BNLH join)
 flush status;
 select count(*) from t0 A, t0 B, t0 C, t0 D where D.a in (select a from t1 E);
 count(*)
@@ -1192,12 +1192,12 @@ insert into t3 select * from t1;
 insert into t3 values (1),(2);
 explain select * from t2 where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Start temporary
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t1	hash	NULL	hj_key	4	test.t2.a	4	Using where; End temporary; Using join buffer (flat, BNLH join)
 explain select * from t2 where a 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	Start temporary
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t2	hash	NULL	hj_key	5	test.t2.a	2	Using where; End temporary; Using join buffer (flat, BNLH join)
 explain select * from t2 where a in (select a from t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Start temporary
@@ -1211,8 +1211,8 @@ create table t1 (a decimal);
 insert into t1 values (1),(2);
 explain select * from t1 where a 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	Start temporary
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	t1	hash	NULL	hj_key	6	test.t1.a	2	Using where; End temporary; Using join buffer (flat, BNLH join)
 drop table t1;
 set @@optimizer_switch=@save_optimizer_switch;
 create table t1 (a int);

mysql-test/r/subselect_sj2_jcl6.result

@@ -138,8 +138,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	ot	hash	NULL	hj_key	5	test.it.a	32	Using where; Using join buffer (flat, BNLH join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -206,8 +206,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	22	
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer (flat, BNL join)
-2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
+1	PRIMARY	ot	hash	NULL	hj_key	5	test.it.a	52	Using where; Using join buffer (flat, BNLH join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -588,7 +588,7 @@ explain
 select * from t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t3));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	t2	hash	NULL	hj_key	5	test.t1.a	3	Using where; Using join buffer (flat, BNLH join)
 2	DEPENDENT SUBQUERY	t3	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
 drop table t0, t1, t2, t3;
 create table t1 (a int);

mysql-test/r/subselect_sj_jcl6.result

 set @save_optimizer_switch_jcl6=@@optimizer_switch;
 set @@optimizer_switch='semijoin_with_cache=on';
 set @@optimizer_switch='outer_join_with_cache=on';
+set @@optimizer_switch='join_cache_hashed=off';
 set join_cache_level=6;
 show variables like 'join_cache_level';
 Variable_name	Value

mysql-test/suite/innodb/r/innodb_mysql.result

@@ -2656,7 +2656,7 @@ SELECT t1.pk FROM t1,t2
 WHERE t1.pk = t2.pk AND t2.pk <> 8;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	11	Using where; Using index
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	4	test.t1.pk	1	Using index; Using join buffer (flat, BNLH join)
+1	SIMPLE	t2	hash	PRIMARY	PRIMARY	4	test.t1.pk	13	Using index; Using join buffer (flat, BNLH join)
 SELECT t1.pk FROM t1,t2 
 WHERE t1.pk = t2.pk AND t2.pk <> 8;
 pk

mysql-test/t/join_cache.test

@@ -58,6 +58,60 @@ SELECT City.Name, Country.Name, CountryLanguage.Language
 set join_cache_level=2;
 show variables like 'join_cache_level';
 
+EXPLAIN
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+EXPLAIN
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+set join_cache_level=3;
+show variables like 'join_cache_level';
+
+EXPLAIN
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+EXPLAIN
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+set join_cache_level=4;
+show variables like 'join_cache_level';
+
 EXPLAIN
 SELECT City.Name, Country.Name FROM City,Country
   WHERE City.Country=Country.Code AND 
@@ -116,6 +170,60 @@ SELECT City.Name, Country.Name, CountryLanguage.Language
 set join_cache_level=2;
 show variables like 'join_cache_level';
 
+EXPLAIN
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+EXPLAIN
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+set join_cache_level=3;
+show variables like 'join_cache_level';
+
+EXPLAIN
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+SELECT City.Name, Country.Name FROM City,Country
+  WHERE City.Country=Country.Code AND 
+        Country.Name LIKE 'L%' AND City.Population > 100000;
+
+EXPLAIN
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+SELECT City.Name, Country.Name, CountryLanguage.Language
+  FROM City,Country,CountryLanguage
+  WHERE City.Country=Country.Code AND
+        CountryLanguage.Country=Country.Code AND
+        City.Name LIKE 'L%' AND Country.Population > 3000000 AND
+        CountryLanguage.Percentage > 50;
+
+set join_cache_level=4;
+show variables like 'join_cache_level';
+
 EXPLAIN
 SELECT City.Name, Country.Name FROM City,Country
   WHERE City.Country=Country.Code AND 
@@ -2642,13 +2750,13 @@ SET SESSION optimizer_switch = 'outer_join_with_cache=on';
 
 SET SESSION join_cache_level = 6;
 EXPLAIN
-SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0 ;
-SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0 ;
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0;
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0;
 
 SET SESSION join_cache_level = 5;
 EXPLAIN
-SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0 ;
-SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0 ;
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0;
+SELECT * FROM t1 LEFT JOIN t2 JOIN t3 ON t3.a3 = t2.a2 ON t3.b3 <> 0;
 
 SET SESSION optimizer_switch = 'outer_join_with_cache=off';
 SET SESSION join_cache_level = DEFAULT;

mysql-test/t/subselect_sj_jcl6.test

@@ -5,6 +5,7 @@
 set @save_optimizer_switch_jcl6=@@optimizer_switch;
 set @@optimizer_switch='semijoin_with_cache=on';
 set @@optimizer_switch='outer_join_with_cache=on';
+set @@optimizer_switch='join_cache_hashed=off';
 
 set join_cache_level=6;
 show variables like 'join_cache_level';

sql/opt_subselect.cc

@@ -1326,13 +1326,19 @@ static uint get_tmp_table_rec_length(List<Item> &items)
 bool find_eq_ref_candidate(TABLE *table, table_map sj_inner_tables)
 {
   KEYUSE *keyuse= table->reginfo.join_tab->keyuse;
-  uint key;
 
   if (keyuse)
   {
     while (1) /* For each key */
     {
-      key= keyuse->key;
+      if (keyuse->is_for_hash_join())
+      {
+        keyuse++;
+        if (keyuse->table != table)
+          return FALSE;
+        continue;
+      }
+      uint key= keyuse->key;
       KEY *keyinfo= table->key_info + key;
       key_part_map bound_parts= 0;
       if (keyinfo->flags & HA_NOSAME)

sql/sql_join_cache.cc

@@ -1052,9 +1052,8 @@ bool JOIN_CACHE::check_emb_key_usage()
   CACHE_FIELD *copy;
   CACHE_FIELD *copy_end;
   uint len= 0;
-  TABLE *table= join_tab->table;
   TABLE_REF *ref= &join_tab->ref;
-  KEY *keyinfo= table->key_info+ref->key;
+  KEY *keyinfo= join_tab->get_keyinfo_by_key_no(ref->key);
 
   /* 
     If some of the key arguments are not from the local cache the key
@@ -2520,7 +2519,7 @@ int JOIN_CACHE_HASHED::init()
   pack_length+= get_size_of_rec_offset(); 
   pack_length_with_blob_ptrs+= get_size_of_rec_offset();
 
-  ref_key_info= join_tab->table->key_info+join_tab->ref.key;
+  ref_key_info= join_tab->get_keyinfo_by_key_no(join_tab->ref.key);
   ref_used_key_parts= join_tab->ref.key_parts;
 
   hash_func= &JOIN_CACHE_HASHED::get_hash_idx_simple;
@@ -3427,7 +3426,7 @@ uchar *JOIN_CACHE_BNLH::get_matching_chain_by_join_key()
   uchar *key_ref_ptr;
   TABLE *table= join_tab->table;
   TABLE_REF *ref= &join_tab->ref;
-  KEY *keyinfo= table->key_info+ref->key;
+  KEY *keyinfo= join_tab->get_keyinfo_by_key_no(ref->key);
   /* Build the join key value out of the record in the record buffer */
   key_copy(key_buff, table->record[0], keyinfo, key_length, TRUE);
   /* Look for this key in the join buffer */

sql/sql_select.h

@@ -39,6 +39,11 @@
 /* Values in optimize */
 #define KEY_OPTIMIZE_EXISTS		1
 #define KEY_OPTIMIZE_REF_OR_NULL	2
+#define KEY_OPTIMIZE_EQ	                4
+
+inline uint get_hash_join_key_no() { return MAX_KEY; }
+
+inline bool is_hash_join_key_no(uint key) { return key == MAX_KEY; }
 
 typedef struct keyuse_t {
   TABLE *table;
@@ -68,6 +73,8 @@ typedef struct keyuse_t {
      MAX_UINT  Otherwise
   */
   uint         sj_pred_no;
+
+  bool is_for_hash_join() { return is_hash_join_key_no(key); }
 } KEYUSE;
 
 class store_key;
@@ -127,7 +134,8 @@ typedef struct st_table_ref
 */
 enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF,
 		 JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL,
-		 JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE};
+		 JT_UNIQUE_SUBQUERY, JT_INDEX_SUBQUERY, JT_INDEX_MERGE,
+                 JT_HASH};
 
 class JOIN;
 
@@ -159,6 +167,8 @@ typedef struct st_join_table {
   st_join_table() {}                          /* Remove gcc warning */
   TABLE		*table;
   KEYUSE	*keyuse;			/**< pointer to first used key */
+  KEY           *hj_key;       /**< descriptor of the used best hash join key
+				    not supported by any index                 */
   SQL_SELECT	*select;
   COND		*select_cond;
   COND          *on_precond;    /**< part of on condition to check before
@@ -408,6 +418,11 @@ typedef struct st_join_table {
   double get_partial_join_cardinality() { return partial_join_cardinality; }
   bool hash_join_is_possible();
   int make_scan_filter();
+  bool is_ref_for_hash_join() { return is_hash_join_key_no(ref.key); }
+  KEY *get_keyinfo_by_key_no(uint key) 
+  {
+    return (is_hash_join_key_no(key) ? hj_key : table->key_info+key);
+  }
 } JOIN_TAB;
 
 
@@ -681,6 +696,15 @@ class JOIN :public Sql_alloc
   Item      *tmp_having; ///< To store having when processed temporary table
   Item      *having_history; ///< Store having for explain
   ulonglong  select_options;
+  /* 
+    Bitmap of allowed types of the join caches that
+    can be used for join operations
+  */
+  uint allowed_join_cache_types;
+  bool allowed_semijoin_with_cache;
+  bool allowed_outer_join_with_cache;
+  /* Maximum level of the join caches that can be used for join operations */ 
+  uint max_allowed_join_cache_level;
   select_result *result;
   TMP_TABLE_PARAM tmp_table_param;
   MYSQL_LOCK *lock;
@@ -947,6 +971,12 @@ class JOIN :public Sql_alloc
   bool shrink_join_buffers(JOIN_TAB *jt, 
                            ulonglong curr_space,
                            ulonglong needed_space);
+  void set_allowed_join_cache_types();
+  bool is_allowed_hash_join_access()
+  { 
+    return test(allowed_join_cache_types & JOIN_CACHE_HASHED_BIT) &&
+           max_allowed_join_cache_level > JOIN_CACHE_HASHED_BIT;
+  }
 
 private:
   /**

sql/table.cc

@@ -2344,7 +2344,7 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
   /* Allocate bitmaps */
 
   bitmap_size= share->column_bitmap_size;
-  if (!(bitmaps= (uchar*) alloc_root(&outparam->mem_root, bitmap_size*4)))
+  if (!(bitmaps= (uchar*) alloc_root(&outparam->mem_root, bitmap_size*5)))
     goto err;
   bitmap_init(&outparam->def_read_set,
               (my_bitmap_map*) bitmaps, share->fields, FALSE);
@@ -2354,6 +2354,8 @@ int open_table_from_share(THD *thd, TABLE_SHARE *share, const char *alias,
               (my_bitmap_map*) (bitmaps+bitmap_size*2), share->fields, FALSE);
   bitmap_init(&outparam->tmp_set,
               (my_bitmap_map*) (bitmaps+bitmap_size*3), share->fields, FALSE);
+  bitmap_init(&outparam->eq_join_set,
+              (my_bitmap_map*) (bitmaps+bitmap_size*4), share->fields, FALSE);
   outparam->default_column_bitmaps();
 
   /* The table struct is now initialized;  Open the table */
@@ -5205,6 +5207,52 @@ bool TABLE::alloc_keys(uint key_count)
 }
 
 
+void TABLE::create_key_part_by_field(KEY *keyinfo,
+                                     KEY_PART_INFO *key_part_info,
+                                     Field *field)
+{   
+  field->flags|= PART_KEY_FLAG;
+  key_part_info->null_bit= field->null_bit;
+  key_part_info->null_offset= (uint) (field->null_ptr -
+                                      (uchar*) record[0]);
+  key_part_info->field= field;
+  key_part_info->offset= field->offset(record[0]);
+  key_part_info->length=   (uint16) field->pack_length();
+  keyinfo->key_length+= key_part_info->length;
+  key_part_info->key_part_flag= 0;
+  /* TODO:
+    The below method of computing the key format length of the
+    key part is a copy/paste from opt_range.cc, and table.cc.
+    This should be factored out, e.g. as a method of Field.
+    In addition it is not clear if any of the Field::*_length
+    methods is supposed to compute the same length. If so, it
+    might be reused.
+  */
+  key_part_info->store_length= key_part_info->length;
+
+  if (field->real_maybe_null())
+  {
+    key_part_info->store_length+= HA_KEY_NULL_LENGTH;
+    keyinfo->key_length+= HA_KEY_NULL_LENGTH;
+  }
+  if (field->type() == MYSQL_TYPE_BLOB || 
+      field->real_type() == MYSQL_TYPE_VARCHAR)
+  {
+    key_part_info->store_length+= HA_KEY_BLOB_LENGTH;
+    keyinfo->key_length+= HA_KEY_BLOB_LENGTH; // ???
+    key_part_info->key_part_flag|=
+      field->type() == MYSQL_TYPE_BLOB ? HA_BLOB_PART: HA_VAR_LENGTH_PART;
+  }
+
+  key_part_info->type=     (uint8) field->key_type();
+  key_part_info->key_type =
+    ((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
+    (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT1 ||
+    (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT2) ?
+    0 : FIELDFLAG_BINARY;
+}
+
+
 /**
   Add a key to a temporary  table
 
@@ -5255,54 +5303,18 @@ bool TABLE::add_tmp_key(uint key, uint key_parts,
   if (!keyinfo->rec_per_key)
     return TRUE;
   bzero(keyinfo->rec_per_key, sizeof(ulong)*key_parts);
+
   for (i= 0; i < key_parts; i++)
   {
     reg_field= field + next_field_no(arg);
     if (key_start)
       (*reg_field)->key_start.set_bit(key);
-    key_start= FALSE;
     (*reg_field)->part_of_key.set_bit(key);
-    (*reg_field)->flags|= PART_KEY_FLAG;
-    key_part_info->null_bit= (*reg_field)->null_bit;
-    key_part_info->null_offset= (uint) ((*reg_field)->null_ptr -
-                                          (uchar*) record[0]);
-    key_part_info->field=    *reg_field;
-    key_part_info->offset=   (*reg_field)->offset(record[0]);
-    key_part_info->length=   (uint16) (*reg_field)->pack_length();
-    keyinfo->key_length+= key_part_info->length;
-    key_part_info->key_part_flag= 0;
-    /* TODO:
-      The below method of computing the key format length of the
-      key part is a copy/paste from opt_range.cc, and table.cc.
-      This should be factored out, e.g. as a method of Field.
-      In addition it is not clear if any of the Field::*_length
-      methods is supposed to compute the same length. If so, it
-      might be reused.
-    */
-    key_part_info->store_length= key_part_info->length;
-
-    if ((*reg_field)->real_maybe_null())
-    {
-      key_part_info->store_length+= HA_KEY_NULL_LENGTH;
-      keyinfo->key_length+= HA_KEY_NULL_LENGTH;
-      if (unique)
-        keyinfo->flags|= HA_NULL_ARE_EQUAL;     // def. that NULL == NULL
-    }
-    if ((*reg_field)->type() == MYSQL_TYPE_BLOB || 
-        (*reg_field)->real_type() == MYSQL_TYPE_VARCHAR)
-    {
-      key_part_info->store_length+= HA_KEY_BLOB_LENGTH;
-      keyinfo->key_length+= HA_KEY_BLOB_LENGTH; // ???
-    }
-
-    key_part_info->type=     (uint8) (*reg_field)->key_type();
-    key_part_info->key_type =
-      ((ha_base_keytype) key_part_info->type == HA_KEYTYPE_TEXT ||
-       (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT1 ||
-       (ha_base_keytype) key_part_info->type == HA_KEYTYPE_VARTEXT2) ?
-      0 : FIELDFLAG_BINARY;
+    create_key_part_by_field(keyinfo, key_part_info, *reg_field);
+    key_start= FALSE;
     key_part_info++;
   }
+
   set_if_bigger(s->max_key_length, keyinfo->key_length);
   s->keys++;
   return FALSE;

sql/table.h

@@ -725,6 +725,7 @@ struct st_table {
   uchar		*null_flags;
   my_bitmap_map	*bitmap_init_value;
   MY_BITMAP     def_read_set, def_write_set, def_vcol_set, tmp_set; 
+  MY_BITMAP     eq_join_set;         /* used to mark equi-joined fields */
   MY_BITMAP     *read_set, *write_set, *vcol_set; /* Active column sets */
   /*
    The ID of the query that opened and is using this table. Has different
@@ -955,6 +956,8 @@ struct st_table {
   bool add_tmp_key(uint key, uint key_parts,
                    uint (*next_field_no) (uchar *), uchar *arg,
                    bool unique);
+  void create_key_part_by_field(KEY *keyinfo, KEY_PART_INFO *key_part_info,
+                                Field *field);
   bool is_children_attached(void);
   inline void enable_keyread()
   {