Fixed LP bug #891953.

Due to this bug the function SEL_IMERGE::or_sel_tree_with_checks()
could build an inconsistent merge tree if one of the SEL_TREEs in the
resulting index merge happened to contain a full key range.
This could trigger an assertion failure.

mysql-test/r/range_vs_index_merge.result

@@ -1427,4 +1427,17 @@ WHERE t1.a>300 AND t1.c!=0 AND t1.b>=350 AND t1.b<=400 AND
 (t1.c=0 OR t1.a=500);
 a	b	c
 DROP TABLE t1;
+CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX idx(b));
+INSERT INTO t1 VALUES (167,9999), (168,10000);
+EXPLAIN
+SELECT * FROM t1
+WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY,idx	NULL	NULL	NULL	2	Using where
+SELECT * FROM t1
+WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+a	b
+167	9999
+168	10000
+DROP TABLE t1;
 set session optimizer_switch='index_merge_sort_intersection=default';

mysql-test/r/range_vs_index_merge_innodb.result

@@ -1428,5 +1428,18 @@ WHERE t1.a>300 AND t1.c!=0 AND t1.b>=350 AND t1.b<=400 AND
 (t1.c=0 OR t1.a=500);
 a	b	c
 DROP TABLE t1;
+CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX idx(b));
+INSERT INTO t1 VALUES (167,9999), (168,10000);
+EXPLAIN
+SELECT * FROM t1
+WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	PRIMARY,idx	PRIMARY	0	NULL	1	Using where
+SELECT * FROM t1
+WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+a	b
+167	9999
+168	10000
+DROP TABLE t1;
 set session optimizer_switch='index_merge_sort_intersection=default';
 SET SESSION STORAGE_ENGINE=DEFAULT;

mysql-test/t/range_vs_index_merge.test

@@ -1074,6 +1074,21 @@ SELECT * FROM t1
 
 DROP TABLE t1;
 
+#
+# LP bug #891953: always true OR    
+#              
+
+CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX idx(b));
+INSERT INTO t1 VALUES (167,9999), (168,10000);
+
+EXPLAIN
+SELECT * FROM t1
+  WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+SELECT * FROM t1
+  WHERE a BETWEEN 4 AND 5 AND b IN (255,4) OR a IN (2,14,25) OR a!=2;
+
+DROP TABLE t1;
+
 #the following command must be the last one in the file
 set session optimizer_switch='index_merge_sort_intersection=default';
 

sql/opt_range.cc

@@ -1208,13 +1208,13 @@ int SEL_IMERGE::or_sel_tree_with_checks(RANGE_OPT_PARAM *param,
 
     if (result)
     {
+      result->keys_map= result_keys;
       if (result_keys.is_clear_all())
         result->type= SEL_TREE::ALWAYS;
       if ((result->type == SEL_TREE::MAYBE) ||
           (result->type == SEL_TREE::ALWAYS))
         return 1;
       /* SEL_TREE::IMPOSSIBLE is impossible here */
-      result->keys_map= result_keys; 
       *or_tree= result;
       was_ored= TRUE;
     }