Back-port from 6.0 of the fix for

BUG#38049 "incorrect rows estimations with references from preceding table"
(from revid:sergefp@mysql.com-20090126194259-ue20il3qro529l4d).
Compared to 6.0 where EXPLAIN indicates "Using index condition", here in join_optimizer.result
we see "Using where"; it's normal; 6.0 shows the same if disabling Index Condition Pushdown.

3 files changed, 84 insertions, 2 deletions

diff --git a/mysql-test/r/join_optimizer.result b/mysql-test/r/join_optimizer.result
new file mode 100644
index 00000000000..9e667506cfa
--- /dev/null
+++ b/mysql-test/r/join_optimizer.result
@@ -0,0 +1,37 @@
+drop table if exists t0,t1,t2,t3;
+#
+# BUG#38049 incorrect rows estimations with references from preceding table
+#
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+create table t1 (a varchar(32));
+insert into t1 values ('owner'),('requester'),('admincc'),('cc');
+CREATE TABLE t2 (
+id int(11) NOT NULL,
+type varchar(32) default NULL,
+PRIMARY KEY  (id)
+);
+insert into t2 values (1,'owner'), (2,'admincc');
+CREATE TABLE t3 (
+id int(11) NOT NULL,
+domain varchar(32) default NULL,
+type varchar(32) default NULL,
+PRIMARY KEY  (id)
+);
+set @domain='system';
+set @pk=0;
+INSERT INTO t3 select @pk:=@pk+1, 'system', t1.a from t1;
+INSERT INTO t3 select @pk:=@pk+1, 'queue', t1.a from t1, t0 where t0.a<3;
+INSERT INTO t3 select @pk:=@pk+1, 'ticket', t1.a from t1, t0 A, t0 B, t0 C;
+CREATE INDEX groups_d ON t3(domain);
+CREATE INDEX groups_t ON t3(type);
+CREATE INDEX groups_td ON t3(type, domain);
+CREATE INDEX groups_dt ON t3(domain, type);
+For table g this must use ref(groups_dt) and #rows should be around 15 and not 335:
+explain 
+SELECT STRAIGHT_JOIN g.id FROM t2 a, t3 g USE INDEX(groups_dt) 
+WHERE g.domain = 'queue' AND g.type = a.type;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	a	ALL	NULL	NULL	NULL	NULL	2	
+1	SIMPLE	g	ref	groups_dt	groups_dt	70	const,test.a.type	13	Using where
+drop table t0,t1,t2,t3;
diff --git a/mysql-test/r/view.result b/mysql-test/r/view.result
index e23e8930ddb..69bcf349f51 100644
--- a/mysql-test/r/view.result
+++ b/mysql-test/r/view.result
@@ -2342,11 +2342,11 @@ CREATE VIEW v2 AS SELECT t3.* FROM t1,t3 WHERE t1.a=t3.a;
 EXPLAIN SELECT t1.* FROM t1 JOIN t2 WHERE t1.a=t2.a AND t1.b=t2.b AND t1.a=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	5	const	1	Using where; Using index
-1	SIMPLE	t2	ref	a	a	10	const,test.t1.b	2	Using where; Using index
+1	SIMPLE	t2	ref	a	a	10	const,test.t1.b	1	Using where; Using index
 EXPLAIN SELECT * FROM v1 WHERE a=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	5	const	1	Using where; Using index
-1	SIMPLE	t2	ref	a	a	10	const,test.t1.b	2	Using where; Using index
+1	SIMPLE	t2	ref	a	a	10	const,test.t1.b	1	Using where; Using index
 EXPLAIN SELECT * FROM v2 WHERE a=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	5	const	1	Using where; Using index
diff --git a/mysql-test/t/join_optimizer.test b/mysql-test/t/join_optimizer.test
new file mode 100644
index 00000000000..3afe82113b9
--- /dev/null
+++ b/mysql-test/t/join_optimizer.test
@@ -0,0 +1,45 @@
+--disable_warnings
+drop table if exists t0,t1,t2,t3;
+--enable_warnings
+
+--echo #
+--echo # BUG#38049 incorrect rows estimations with references from preceding table
+--echo #
+
+create table t0 (a int);
+insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
+
+create table t1 (a varchar(32));
+insert into t1 values ('owner'),('requester'),('admincc'),('cc');
+
+CREATE TABLE t2 (
+  id int(11) NOT NULL,
+  type varchar(32) default NULL,
+  PRIMARY KEY  (id)
+);
+insert into t2 values (1,'owner'), (2,'admincc');
+
+
+CREATE TABLE t3 (
+  id int(11) NOT NULL,
+  domain varchar(32) default NULL,
+  type varchar(32) default NULL,
+  PRIMARY KEY  (id)
+);
+
+set @domain='system';
+set @pk=0;
+INSERT INTO t3 select @pk:=@pk+1, 'system', t1.a from t1;
+INSERT INTO t3 select @pk:=@pk+1, 'queue', t1.a from t1, t0 where t0.a<3;
+INSERT INTO t3 select @pk:=@pk+1, 'ticket', t1.a from t1, t0 A, t0 B, t0 C;
+
+CREATE INDEX groups_d ON t3(domain);
+CREATE INDEX groups_t ON t3(type);
+CREATE INDEX groups_td ON t3(type, domain);
+CREATE INDEX groups_dt ON t3(domain, type);
+--echo For table g this must use ref(groups_dt) and #rows should be around 15 and not 335:
+explain 
+SELECT STRAIGHT_JOIN g.id FROM t2 a, t3 g USE INDEX(groups_dt) 
+WHERE g.domain = 'queue' AND g.type = a.type;
+
+drop table t0,t1,t2,t3;