Fixed bug mdev-4355.

This patch almost totally revised the patch for bug mdev-4177.
The latter had too many defects. In particular, it did not
propagate multiple equalities formed when merging a degenerate
disjunct into underlying AND formula.

mysql-test/r/select.result

@@ -5155,7 +5155,7 @@ a	b	c
 8	8	8
 DROP TABLE t1,t2;
 #
-# Bug mdev-4413: another manifestations of bug mdev-2474
+# Bug mdev-4413: another manifestations of bug mdev-4274
 #                (valgrind complains)
 #
 CREATE TABLE t1 (a int, b int) ENGINE=MyISAM;
@@ -5167,4 +5167,54 @@ WHERE c = a AND
 ( 0 OR ( b BETWEEN 45 AND 300 OR a > 45 AND a < 100 ) AND b = c );
 a	b	c
 DROP TABLE t1, t2;
+#
+# Bug mdev-4355: equalities from the result of simplification of OR
+#                are not propagated to lower AND levels
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,101),(2,102),(3,103),(4,104),(5,11);
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where 0
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 5) and (`test`.`t1`.`a` = 5))
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+DROP TABLE t1;
 End of 5.3 tests

mysql-test/r/select_jcl6.result

@@ -5166,7 +5166,7 @@ a	b	c
 8	8	8
 DROP TABLE t1,t2;
 #
-# Bug mdev-4413: another manifestations of bug mdev-2474
+# Bug mdev-4413: another manifestations of bug mdev-4274
 #                (valgrind complains)
 #
 CREATE TABLE t1 (a int, b int) ENGINE=MyISAM;
@@ -5178,6 +5178,56 @@ WHERE c = a AND
 ( 0 OR ( b BETWEEN 45 AND 300 OR a > 45 AND a < 100 ) AND b = c );
 a	b	c
 DROP TABLE t1, t2;
+#
+# Bug mdev-4355: equalities from the result of simplification of OR
+#                are not propagated to lower AND levels
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,101),(2,102),(3,103),(4,104),(5,11);
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where 0
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 5) and (`test`.`t1`.`a` = 5))
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+DROP TABLE t1;
 End of 5.3 tests
 set join_cache_level=default;
 show variables like 'join_cache_level';

mysql-test/r/select_pkeycache.result

@@ -5155,7 +5155,7 @@ a	b	c
 8	8	8
 DROP TABLE t1,t2;
 #
-# Bug mdev-4413: another manifestations of bug mdev-2474
+# Bug mdev-4413: another manifestations of bug mdev-4274
 #                (valgrind complains)
 #
 CREATE TABLE t1 (a int, b int) ENGINE=MyISAM;
@@ -5167,4 +5167,54 @@ WHERE c = a AND
 ( 0 OR ( b BETWEEN 45 AND 300 OR a > 45 AND a < 100 ) AND b = c );
 a	b	c
 DROP TABLE t1, t2;
+#
+# Bug mdev-4355: equalities from the result of simplification of OR
+#                are not propagated to lower AND levels
+#
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,101),(2,102),(3,103),(4,104),(5,11);
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`a` = 5) and (`test`.`t1`.`b` <> 1))
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+a	b
+5	11
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where 0
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = 5) and (`test`.`t1`.`a` = 5))
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+a	b
+DROP TABLE t1;
 End of 5.3 tests

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`.`t2`.`i2` > 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`.`t3`.`i3` > 0))
 SELECT * FROM t1 
 WHERE i1 IN (SELECT i3 FROM t2, t3 WHERE i3 > 0 AND i3 = i2 OR 1=2);
 i1

mysql-test/t/select.test

@@ -4326,7 +4326,7 @@ SELECT * FROM t1 INNER JOIN t2 ON ( c = a )
 DROP TABLE t1,t2;
 
 --echo #
---echo # Bug mdev-4413: another manifestations of bug mdev-2474
+--echo # Bug mdev-4413: another manifestations of bug mdev-4274
 --echo #                (valgrind complains)
 --echo #
 
@@ -4342,4 +4342,34 @@ SELECT * FROM t1, t2
 
 DROP TABLE t1, t2;
 
+--echo #
+--echo # Bug mdev-4355: equalities from the result of simplification of OR
+--echo #                are not propagated to lower AND levels
+--echo #
+
+CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (1,101),(2,102),(3,103),(4,104),(5,11);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+SELECT * FROM t1 WHERE (1 != 1 OR a = 5) AND (b != 1 OR a = 1);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (1 != 1 OR a = 5);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+SELECT * FROM t1 WHERE (b != 1 OR a = 1) AND (a = 5 OR 1 != 1);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+SELECT * FROM t1 WHERE (b = 1 OR a = 1) AND (b = 5 AND a = 5 OR 1 != 1);
+
+EXPLAIN EXTENDED
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+SELECT * FROM t1 WHERE (b = 1 OR a = 5) AND (b = 5 AND a = 5 OR 1 != 1);
+
+DROP TABLE t1;
+
 --echo End of 5.3 tests

sql/item_cmpfunc.cc

@@ -5608,10 +5608,12 @@ void Item_equal::merge(Item_equal *item)
   @brief
   Merge members of another Item_equal object into this one
   
-  @param item    multiple equality whose members are to be merged
+  @param item         multiple equality whose members are to be merged
+  @param save_merged  keep the list of equalities in 'item' intact
+                      (e.g. for other merges)
 
   @details
-  If the Item_equal 'item' happened to have some elements of the list
+  If the Item_equal 'item' happens to have some elements of the list
   of equal items belonging to 'this' object then the function merges
   the equal items from 'item' into this list.
   If both lists contains constants and they are different then
@@ -5626,24 +5628,45 @@ void Item_equal::merge(Item_equal *item)
   The method 'merge' just joins the list of equal items belonging to 'item'
   to the list of equal items belonging to this object assuming that the lists
   are disjoint. It would be more correct to call the method 'join'.
-  The method 'merge_with_check' really merges two lists of equal items if they
-  have common members.  
+  The method 'merge_into_with_check' really merges two lists of equal items if
+  they have common members.  
 */
   
-bool Item_equal::merge_with_check(Item_equal *item)
+bool Item_equal::merge_with_check(Item_equal *item, bool save_merged)
 {
   bool intersected= FALSE;
-  Item_equal_fields_iterator_slow fi(*this);
+  Item_equal_fields_iterator_slow fi(*item);
+  
   while (fi++)
   {
-    if (item->contains(fi.get_curr_field()))
+    if (contains(fi.get_curr_field()))
     {
-      fi.remove();
       intersected= TRUE;
+      if (!save_merged)
+        fi.remove();
     }
   }
   if (intersected)
-    item->merge(this);
+  {
+    if (!save_merged)
+      merge(item);
+    else
+    {
+      Item *c= item->get_const();
+      if (c)
+        add_const(c);
+      if (!cond_false)
+      {
+        Item *item;
+        fi.rewind();
+        while ((item= fi++))
+	{
+          if (!contains(fi.get_curr_field()))
+            add(item);
+        }
+      }
+    }         
+  }
   return intersected;
 }
 
@@ -5652,17 +5675,25 @@ bool Item_equal::merge_with_check(Item_equal *item)
   @brief
   Merge this object into a list of Item_equal objects 
   
-  @param list   the list of Item_equal objects to merge into
+  @param list                 the list of Item_equal objects to merge into
+  @param save_merged          keep the list of equalities in 'this' intact
+                              (e.g. for other merges)
+  @param only_intersected     do not merge if there are no common members
+                              in any of Item_equal objects from the list
+                              and this Item_equal
 
   @details
   If the list of equal items from 'this' object contains common members
   with the lists of equal items belonging to Item_equal objects from 'list'
   then all involved Item_equal objects e1,...,ek are merged into one 
-  Item equal that replaces e1,...,ek in the 'list'. Otherwise this
+  Item equal that replaces e1,...,ek in the 'list'. Otherwise, in the case
+  when the value of the parameter only_if_intersected is false, this
   Item_equal is joined to the 'list'.
 */
 
-void Item_equal::merge_into_list(List<Item_equal> *list)
+void Item_equal::merge_into_list(List<Item_equal> *list,
+                                 bool save_merged,
+                                 bool only_intersected)
 {
   Item_equal *item;
   List_iterator<Item_equal> it(*list);
@@ -5671,16 +5702,16 @@ void Item_equal::merge_into_list(List<Item_equal> *list)
   {
     if (!merge_into)
     {
-      if (merge_with_check(item))
+      if (item->merge_with_check(this, save_merged))
         merge_into= item;
     }
     else
     {
-      if (item->merge_with_check(merge_into))
+      if (merge_into->merge_with_check(item, false))
         it.remove();
     }
   }
-  if (!merge_into)
+  if (!only_intersected && !merge_into)
     list->push_back(this);
 }
 

sql/item_cmpfunc.h

@@ -1761,8 +1761,9 @@ public:
   /** Get number of field items / references to field items in this object */   
   uint n_field_items() { return equal_items.elements-test(with_const); }
   void merge(Item_equal *item);
-  bool merge_with_check(Item_equal *equal_item);
-  void merge_into_list(List<Item_equal> *list);
+  bool merge_with_check(Item_equal *equal_item, bool save_merged);
+  void merge_into_list(List<Item_equal> *list, bool save_merged,
+                      bool only_intersected);
   void update_const();
   enum Functype functype() const { return MULT_EQUAL_FUNC; }
   longlong val_int();