After merge fix.

mysql-test/r/index_merge_myisam.result

@@ -286,7 +286,7 @@ NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL
 explain select * from (select * from t1 where key1 = 3 or key2 =3) as Z where key8 >5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
-2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where
+2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where; Using index
 create table t3 like t0;
 insert into t3 select * from t0;
 alter table t3 add key9 int not null, add index i9(key9);
@@ -696,6 +696,17 @@ explain select a from t2 where a='ab';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ref	a	a	6	const	1	Using where
 drop table t2;
+CREATE TABLE t1(c1 INT, c2 INT DEFAULT 0, c3 CHAR(255) DEFAULT '',
+KEY(c1), KEY(c2), KEY(c3));
+INSERT INTO t1(c1) VALUES(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),
+(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0),(0);
+INSERT INTO t1 VALUES(0,0,0);
+CREATE TABLE t2(c1 int);
+INSERT INTO t2 VALUES(1);
+DELETE t1 FROM t1,t2 WHERE t1.c1=0 AND t1.c2=0;
+SELECT * FROM t1;
+c1	c2	c3
+DROP TABLE t1,t2;
 #---------------- Index merge test 2 -------------------------------------------
 SET SESSION STORAGE_ENGINE = MyISAM;
 drop table if exists t1,t2;

sql/opt_range.cc

@@ -1002,6 +1002,11 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
     if (file) 
     {
       range_end();
+      if (head->key_read)
+      {
+        head->key_read= 0;
+        file->extra(HA_EXTRA_NO_KEYREAD);
+      }
       if (free_file)
       {
         DBUG_PRINT("info", ("Freeing separate handler 0x%lx (free: %d)", (long) file,
@@ -1010,10 +1015,6 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
         file->close();
         delete file;
       }
-      else
-      {
-        file->extra(HA_EXTRA_NO_KEYREAD);
-      }
     }
     delete_dynamic(&ranges); /* ranges are allocated in alloc */
     free_root(&alloc,MYF(0));
@@ -1195,7 +1196,11 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   org_file= head->file;
   head->file= file;
   /* We don't have to set 'head->keyread' here as the 'file' is unique */
-  head->mark_columns_used_by_index(index);
+  if (!head->no_keyread)
+  {
+    head->key_read= 1;
+    head->mark_columns_used_by_index(index);
+  }
   head->prepare_for_position();
   head->file= org_file;
   bitmap_copy(&column_bitmap, head->read_set);