Fixed bug mdev-4971.

The function propagate_new_equalities() did not updated properly
the references to inherited multiple equalities.

6 files changed, 102 insertions, 2 deletions

diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result
index f5744c8e3d0..f0de9622368 100644
--- a/mysql-test/r/select.result
+++ b/mysql-test/r/select.result
@@ -5254,4 +5254,29 @@ SELECT * FROM t1, t2
 WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
 i1	j1	i2
 DROP TABLE t1,t2;
+#
+# Bug mdev-4971: equality propagation after merging degenerate 
+#                disjunction into embedding AND level 
+#
+CREATE TABLE t1 (pk1 int, a1 int, b1 int, PRIMARY KEY(pk1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,10,100), (2,20,200) ;
+CREATE TABLE t2 (pk2 int, a2 int, PRIMARY KEY(pk2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,1);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t2	system	PRIMARY	NULL	NULL	NULL	1	100.00	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`pk1` AS `pk1`,`test`.`t1`.`a1` AS `a1`,`test`.`t1`.`b1` AS `b1`,1 AS `pk2`,1 AS `a2` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`a1` = 1) and ((`test`.`t1`.`b1` = 6) or (1 > 4)))
+INSERT INTO t1 VALUES (3,1,6);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+3	1	6	1	1
+DROP TABLE t1,t2;
 End of 5.3 tests
diff --git a/mysql-test/r/select_jcl6.result b/mysql-test/r/select_jcl6.result
index eea9d318f04..3c3d6188301 100644
--- a/mysql-test/r/select_jcl6.result
+++ b/mysql-test/r/select_jcl6.result
@@ -5265,6 +5265,31 @@ SELECT * FROM t1, t2
 WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
 i1	j1	i2
 DROP TABLE t1,t2;
+#
+# Bug mdev-4971: equality propagation after merging degenerate 
+#                disjunction into embedding AND level 
+#
+CREATE TABLE t1 (pk1 int, a1 int, b1 int, PRIMARY KEY(pk1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,10,100), (2,20,200) ;
+CREATE TABLE t2 (pk2 int, a2 int, PRIMARY KEY(pk2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,1);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t2	system	PRIMARY	NULL	NULL	NULL	1	100.00	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`pk1` AS `pk1`,`test`.`t1`.`a1` AS `a1`,`test`.`t1`.`b1` AS `b1`,1 AS `pk2`,1 AS `a2` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`a1` = 1) and ((`test`.`t1`.`b1` = 6) or (1 > 4)))
+INSERT INTO t1 VALUES (3,1,6);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+3	1	6	1	1
+DROP TABLE t1,t2;
 End of 5.3 tests
 set join_cache_level=default;
 show variables like 'join_cache_level';
diff --git a/mysql-test/r/select_pkeycache.result b/mysql-test/r/select_pkeycache.result
index f5744c8e3d0..f0de9622368 100644
--- a/mysql-test/r/select_pkeycache.result
+++ b/mysql-test/r/select_pkeycache.result
@@ -5254,4 +5254,29 @@ SELECT * FROM t1, t2
 WHERE i1 = i2 AND ( FALSE OR ( j1 > 27 AND j1 < 100 OR j1 <= 3 ) AND j1 = i2 );
 i1	j1	i2
 DROP TABLE t1,t2;
+#
+# Bug mdev-4971: equality propagation after merging degenerate 
+#                disjunction into embedding AND level 
+#
+CREATE TABLE t1 (pk1 int, a1 int, b1 int, PRIMARY KEY(pk1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,10,100), (2,20,200) ;
+CREATE TABLE t2 (pk2 int, a2 int, PRIMARY KEY(pk2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,1);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t2	system	PRIMARY	NULL	NULL	NULL	1	100.00	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`pk1` AS `pk1`,`test`.`t1`.`a1` AS `a1`,`test`.`t1`.`b1` AS `b1`,1 AS `pk2`,1 AS `a2` from `test`.`t1` join `test`.`t2` where ((`test`.`t1`.`a1` = 1) and ((`test`.`t1`.`b1` = 6) or (1 > 4)))
+INSERT INTO t1 VALUES (3,1,6);
+SELECT * FROM t1, t2
+WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+pk1	a1	b1	pk2	a2
+3	1	6	1	1
+DROP TABLE t1,t2;
 End of 5.3 tests
diff --git a/mysql-test/r/subselect_sj2_mat.result b/mysql-test/r/subselect_sj2_mat.result
index bf5b95d2d8f..18e3f6ddd34 100644
--- a/mysql-test/r/subselect_sj2_mat.result
+++ b/mysql-test/r/subselect_sj2_mat.result
@@ -1380,7 +1380,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	MATERIALIZED	t3	hash_ALL	NULL	#hash#$hj	5	test.t2.i2	3	100.00	Using where; Using join buffer (flat, BNLH join)
 Warnings:
-Note	1003	select `test`.`t1`.`i1` AS `i1` from `test`.`t1` semi join (`test`.`t2` join `test`.`t3`) where ((`test`.`t3`.`i3` = `test`.`t2`.`i2`) and (`test`.`t1`.`i1` = `test`.`t2`.`i2`) and (`test`.`t3`.`i3` > 0))
+Note	1003	select `test`.`t1`.`i1` AS `i1` from `test`.`t1` semi join (`test`.`t2` join `test`.`t3`) where ((`test`.`t3`.`i3` = `test`.`t2`.`i2`) and (`test`.`t1`.`i1` = `test`.`t2`.`i2`) and (`test`.`t2`.`i2` > 0))
 SELECT * FROM t1 
 WHERE i1 IN (SELECT i3 FROM t2, t3 WHERE i3 > 0 AND i3 = i2 OR 1=2);
 i1
diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test
index bb5a6b9c2fc..9081b93dbf8 100644
--- a/mysql-test/t/select.test
+++ b/mysql-test/t/select.test
@@ -4408,4 +4408,27 @@ SELECT * FROM t1, t2
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # Bug mdev-4971: equality propagation after merging degenerate 
+--echo #                disjunction into embedding AND level 
+--echo #
+
+CREATE TABLE t1 (pk1 int, a1 int, b1 int, PRIMARY KEY(pk1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,10,100), (2,20,200) ;
+
+CREATE TABLE t2 (pk2 int, a2 int, PRIMARY KEY(pk2)) ENGINE=MyISAM;
+INSERT INTO t2 VALUES (1,1);
+
+SELECT * FROM t1, t2
+  WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+EXPLAIN EXTENDED
+SELECT * FROM t1, t2
+  WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+
+INSERT INTO t1 VALUES (3,1,6);
+SELECT * FROM t1, t2
+  WHERE a1 = pk2 AND ( ( b1 = 6 OR a2 > 4 ) AND pk2 = a2 OR pk1 IS NULL );
+
+DROP TABLE t1,t2;
+
 --echo End of 5.3 tests
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 79b11fa934f..4543176ea5e 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13188,7 +13188,8 @@ void propagate_new_equalities(THD *thd, Item *cond,
     {
       Item_cond_and *cond_and= (Item_cond_and *) cond; 
       List<Item_equal> *cond_equalities= &cond_and->cond_equal.current_level;
-      inherited= cond_and->cond_equal.upper_levels;
+      cond_and->cond_equal.upper_levels= inherited;
+      inherited= &cond_and->cond_equal;
       if (!cond_equalities->is_empty() && cond_equalities != new_equalities)
       {
         Item_equal *equal_item;
@@ -13223,6 +13224,7 @@ void propagate_new_equalities(THD *thd, Item *cond,
     Item_equal *equal_item;
     List_iterator<Item_equal> it(*new_equalities);
     Item_equal *equality= (Item_equal *) cond;
+    equality->upper_levels= inherited;
     while ((equal_item= it++))
     {
       equality->merge_with_check(equal_item, true);