BUG#25048 - ERROR 126 : Incorrect key file for table '.XXXX.MYI'; try to

            repair it

Multi-table delete that is optimized with QUICK_RANGE reports table
corruption.

DELETE statement must not use KEYREAD optimization, and sets
table->no_keyread to 1. This was ignored in QUICK_RANGE optimization.

With this fix QUICK_RANGE optimization honors table->no_keyread
value and does not enable KEYREAD when it is requested.

mysql-test/r/index_merge.result

@@ -284,7 +284,7 @@ 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);

mysql-test/r/index_merge_ror.result

@@ -194,3 +194,14 @@ 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;

mysql-test/t/index_merge_ror.test

@@ -250,3 +250,18 @@ select count(a) from t2 ignore index(a,b) where a='AAAAAAAA' and b='AAAAAAAA';
 insert into t2 values ('ab', 'ab', 'uh', 'oh');
 explain select a from t2 where a='ab';
 drop table t2;
+
+#
+# BUG#25048 - ERROR 126 : Incorrect key file for table '.XXXX.MYI'; try to
+#             repair it
+#
+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;
+DROP TABLE t1,t2;

sql/opt_range.cc

@@ -875,7 +875,11 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
     if (file) 
     {
       range_end();
-      file->extra(HA_EXTRA_NO_KEYREAD);
+      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,
@@ -1017,8 +1021,12 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   if (reuse_handler)
   {
     DBUG_PRINT("info", ("Reusing handler %p", file));
-    if (file->extra(HA_EXTRA_KEYREAD) ||
-        file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY) ||
+    if (!head->no_keyread)
+    {
+      head->key_read= 1;
+      file->extra(HA_EXTRA_KEYREAD);
+    }
+    if (file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY) ||
         init() || reset())
     {
       DBUG_RETURN(1);
@@ -1041,9 +1049,12 @@ int QUICK_RANGE_SELECT::init_ror_merged_scan(bool reuse_handler)
   }
   if (file->external_lock(thd, F_RDLCK))
     goto failure;
-
-  if (file->extra(HA_EXTRA_KEYREAD) ||
-      file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY) ||
+  if (!head->no_keyread)
+  {
+    head->key_read= 1;
+    file->extra(HA_EXTRA_KEYREAD);
+  }
+  if (file->extra(HA_EXTRA_RETRIEVE_PRIMARY_KEY) ||
       init() || reset())
   {
     file->external_lock(thd, F_UNLCK);