Merge rurik.mysql.com:/home/igor/mysql-4.1

into rurik.mysql.com:/home/igor/dev/mysql-4.1-0

mysql-test/r/select.result

@@ -2387,3 +2387,16 @@ EXPLAIN SELECT i FROM t1 WHERE i=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	Using index
 DROP TABLE t1;
+CREATE TABLE t1 ( a BLOB, INDEX (a(20)) );
+CREATE TABLE t2 ( a BLOB, INDEX (a(20)) );
+INSERT INTO t1 VALUES ('one'),('two'),('three'),('four'),('five');
+INSERT INTO t2 VALUES ('one'),('two'),('three'),('four'),('five');
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 USE INDEX (a) ON t1.a=t2.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	SIMPLE	t2	ref	a	a	23	test.t1.a	2	
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 FORCE INDEX (a) ON t1.a=t2.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	SIMPLE	t2	ref	a	a	23	test.t1.a	2	
+DROP TABLE t1, t2;

mysql-test/t/select.test

@@ -1930,3 +1930,18 @@ INSERT INTO t1 VALUES (3,'c');
 EXPLAIN SELECT i FROM t1 WHERE i=1;
 
 DROP TABLE t1;
+
+#
+# Test case for bug 7520: a wrong cost of the index for a BLOB field
+#
+
+CREATE TABLE t1 ( a BLOB, INDEX (a(20)) );
+CREATE TABLE t2 ( a BLOB, INDEX (a(20)) );
+
+INSERT INTO t1 VALUES ('one'),('two'),('three'),('four'),('five');
+INSERT INTO t2 VALUES ('one'),('two'),('three'),('four'),('five');
+
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 USE INDEX (a) ON t1.a=t2.a;
+EXPLAIN SELECT * FROM t1 LEFT JOIN t2 FORCE INDEX (a) ON t1.a=t2.a;
+
+DROP TABLE t1, t2;

sql/table.cc

@@ -627,6 +627,7 @@ int openfrm(const char *name, const char *alias, uint db_stat, uint prgflag,
 	    if (!(field->flags & BINARY_FLAG))
 	      keyinfo->flags|= HA_END_SPACE_KEY;
 	  }
+          set_if_bigger(outparam->max_key_length, keyinfo->key_length);
 	  if (i == 0 && key != primary_key)
 	    field->flags |=
 	      ((keyinfo->flags & HA_NOSAME) &&