Merge.

mysql-test/r/range_vs_index_merge.result

@@ -1377,4 +1377,41 @@ SELECT * FROM t1,t2,t3
 WHERE (t2.f3 = 1 OR t3.f1=t2.f1) AND t3.f1 <> t2.f2 AND t3.f2 = t2.f4;
 f1	f1	f2	f3	f4	f1	f2
 DROP TABLE t1,t2,t3;
+CREATE TABLE t1 (
+a int, b int, c int, d int,
+PRIMARY KEY(b), INDEX idx1(d), INDEX idx2(d,b,c)
+);
+INSERT INTO t1 VALUES 
+(0,58,7,7),(0,63,2,0),(0,64,186,8),(0,65,1,-2), (0,71,190,-3),
+(0,72,321,-7),(0,73,0,3),(0,74,5,25),(0,75,5,3);
+SET SESSION optimizer_switch='index_merge_sort_union=off';
+EXPLAIN
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY,idx1,idx2	NULL	NULL	NULL	9	Using where
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+a	b	c	d
+0	58	7	7
+0	64	186	8
+0	73	0	3
+0	74	5	25
+0	75	5	3
+SET SESSION optimizer_switch='index_merge_sort_union=on';
+EXPLAIN
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY,idx1,idx2	NULL	NULL	NULL	9	Using where
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+a	b	c	d
+0	58	7	7
+0	64	186	8
+0	73	0	3
+0	74	5	25
+0	75	5	3
+SET SESSION optimizer_switch=DEFAULT;
+DROP TABLE t1;
 set session optimizer_switch='index_merge_sort_intersection=default';

mysql-test/r/range_vs_index_merge_innodb.result

@@ -1378,5 +1378,42 @@ SELECT * FROM t1,t2,t3
 WHERE (t2.f3 = 1 OR t3.f1=t2.f1) AND t3.f1 <> t2.f2 AND t3.f2 = t2.f4;
 f1	f1	f2	f3	f4	f1	f2
 DROP TABLE t1,t2,t3;
+CREATE TABLE t1 (
+a int, b int, c int, d int,
+PRIMARY KEY(b), INDEX idx1(d), INDEX idx2(d,b,c)
+);
+INSERT INTO t1 VALUES 
+(0,58,7,7),(0,63,2,0),(0,64,186,8),(0,65,1,-2), (0,71,190,-3),
+(0,72,321,-7),(0,73,0,3),(0,74,5,25),(0,75,5,3);
+SET SESSION optimizer_switch='index_merge_sort_union=off';
+EXPLAIN
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY,idx1,idx2	NULL	NULL	NULL	9	Using where
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+a	b	c	d
+0	58	7	7
+0	64	186	8
+0	73	0	3
+0	74	5	25
+0	75	5	3
+SET SESSION optimizer_switch='index_merge_sort_union=on';
+EXPLAIN
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	PRIMARY,idx1,idx2	NULL	NULL	NULL	9	Using where
+SELECT * FROM t1 
+WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+a	b	c	d
+0	58	7	7
+0	64	186	8
+0	73	0	3
+0	74	5	25
+0	75	5	3
+SET SESSION optimizer_switch=DEFAULT;
+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

@@ -1029,5 +1029,34 @@ SELECT * FROM t1,t2,t3
 
 DROP TABLE t1,t2,t3;
 
+#
+# LP bug #823301: index merge union with prossible index scan  
+#              
+#
+
+CREATE TABLE t1 (
+  a int, b int, c int, d int,
+  PRIMARY KEY(b), INDEX idx1(d), INDEX idx2(d,b,c)
+);
+INSERT INTO t1 VALUES 
+ (0,58,7,7),(0,63,2,0),(0,64,186,8),(0,65,1,-2), (0,71,190,-3),
+ (0,72,321,-7),(0,73,0,3),(0,74,5,25),(0,75,5,3);
+
+SET SESSION optimizer_switch='index_merge_sort_union=off';
+EXPLAIN
+SELECT * FROM t1 
+  WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+SELECT * FROM t1 
+  WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+SET SESSION optimizer_switch='index_merge_sort_union=on';
+EXPLAIN
+SELECT * FROM t1 
+  WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+SELECT * FROM t1 
+  WHERE t1.b>7 AND t1.d>1 AND t1.d<>8  OR t1.d>=7 AND t1.d<8 OR t1.d>7;
+SET SESSION optimizer_switch=DEFAULT;
+
+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

@@ -1136,10 +1136,10 @@ int SEL_IMERGE::and_sel_tree(RANGE_OPT_PARAM *param, SEL_TREE *tree,
 
     2. In the second mode, when is_first_check_pass==FALSE :
       2.1. For each rt_j in the imerge that can be ored (see the function
-           sel_trees_can_be_ored), but not must be ored, with rt the function
-           replaces rt_j for a range tree such that for each index for which
-           ranges are defined in both in rt_j and rt  the tree contains the
-           result of oring of these ranges.
+           sel_trees_can_be_ored) with rt the function replaces rt_j for a
+           range tree such that for each index for which ranges are defined
+           in both in rt_j and rt  the tree contains the  result of oring of
+           these ranges.
       2.2. In other cases the function does not produce any imerge.
 
     When is_first_check==TRUE the function returns FALSE in the parameter
@@ -1163,7 +1163,7 @@ int SEL_IMERGE::or_sel_tree_with_checks(RANGE_OPT_PARAM *param,
                                         bool *is_last_check_pass)
 {
   bool was_ored= FALSE;
-  *is_last_check_pass= TRUE;
+  *is_last_check_pass= is_first_check_pass;
   SEL_TREE** or_tree = trees;
   for (uint i= 0; i < n_trees; i++, or_tree++)
   {
@@ -1174,7 +1174,7 @@ int SEL_IMERGE::or_sel_tree_with_checks(RANGE_OPT_PARAM *param,
     {
       bool must_be_ored= sel_trees_must_be_ored(param, *or_tree, tree,
                                                 ored_keys);
-      if (must_be_ored || !is_first_check_pass) 
+      if (must_be_ored || !is_first_check_pass)
       {
         result_keys.clear_all();
         result= *or_tree;
@@ -1210,22 +1210,19 @@ int SEL_IMERGE::or_sel_tree_with_checks(RANGE_OPT_PARAM *param,
     {
       if (result_keys.is_clear_all())
         result->type= SEL_TREE::ALWAYS;
-      *is_last_check_pass= TRUE;
       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;
-      if (is_first_check_pass)
-        return 0;
       was_ored= TRUE;
     }
   }
   if (was_ored)
     return 0;
 
-  if (!*is_last_check_pass && 
+  if (is_first_check_pass && !*is_last_check_pass &&
       !(tree= new SEL_TREE(tree, FALSE, param)))
     return (-1);
   return or_sel_tree(param, tree);
@@ -8382,9 +8379,9 @@ tree_or(RANGE_OPT_PARAM *param,SEL_TREE *tree1,SEL_TREE *tree2)
     /* Build the imerge part of the tree for the formula (1) */
     SEL_TREE *rt1= tree1;
     SEL_TREE *rt2= tree2;
-    if (!no_merges1)
+    if (no_merges1)
       rt1= new SEL_TREE(tree1, TRUE, param);
-    if (!no_merges2)
+    if (no_merges2)
       rt2= new SEL_TREE(tree2, TRUE, param);
     if (!rt1 || !rt2 ||
         result->merges.push_back(imerge_from_ranges) ||
@@ -9079,6 +9076,13 @@ key_or(RANGE_OPT_PARAM *param, SEL_ARG *key1,SEL_ARG *key2)
             key2:               [---]
             tmp:     [---------]
           */
+          if (key2->use_count)
+	  {
+	    SEL_ARG *key2_cpy= new SEL_ARG(*key2);
+            if (key2_cpy)
+              return 0;
+            key2= key2_cpy;
+	  }
           key2->copy_max_to_min(tmp);
           continue;
         }