ctype_ujis.result, ctype_ujis.test, field.cc:

  Bug#6345 Unexpected behaviour with partial indices

mysql-test/r/ctype_ujis.result

@@ -126,3 +126,43 @@ Field	Type	Null	Key	Default	Extra
 a	char(1)				
 b	enum('あ','い')	YES		NULL	
 DROP TABLE t1;
+CREATE TABLE t1
+(
+a INTEGER NOT NULL,
+b VARCHAR(50) NOT NULL DEFAULT '',
+PRIMARY KEY  (a),
+KEY b (b(10))
+) TYPE=InnoDB CHARACTER SET 'ujis' COLLATE 'ujis_japanese_ci';
+INSERT INTO t1 (a, b) VALUES (0, 'aaabbbcccddd');
+INSERT INTO t1 (a, b) VALUES (1, 'eeefffggghhh');
+INSERT INTO t1 (a, b) VALUES (2, 'iiijjjkkkl');
+SELECT t1.* FROM t1 WHERE b='aaabbbcccddd' ORDER BY a;
+a	b
+0	aaabbbcccddd
+SELECT t1.* FROM t1 WHERE b='eeefffggghhh' ORDER BY a;
+a	b
+1	eeefffggghhh
+SELECT t1.* FROM t1 WHERE b='iiijjjkkkl'   ORDER BY a;
+a	b
+2	iiijjjkkkl
+DROP TABLE t1;
+CREATE TABLE t1
+(
+a INTEGER NOT NULL,
+b VARCHAR(50) NOT NULL DEFAULT '',
+PRIMARY KEY  (a),
+KEY b (b(10))
+) TYPE=MyISAM CHARACTER SET 'ujis' COLLATE 'ujis_japanese_ci';
+INSERT INTO t1 (a, b) VALUES (0, 'aaabbbcccddd');
+INSERT INTO t1 (a, b) VALUES (1, 'eeefffggghhh');
+INSERT INTO t1 (a, b) VALUES (2, 'iiijjjkkkl');
+SELECT t1.* FROM t1 WHERE b='aaabbbcccddd' ORDER BY a;
+a	b
+0	aaabbbcccddd
+SELECT t1.* FROM t1 WHERE b='eeefffggghhh' ORDER BY a;
+a	b
+1	eeefffggghhh
+SELECT t1.* FROM t1 WHERE b='iiijjjkkkl'   ORDER BY a;
+a	b
+2	iiijjjkkkl
+DROP TABLE t1;

mysql-test/t/ctype_ujis.test

@@ -83,3 +83,39 @@ CREATE TABLE t1 (
 SHOW CREATE TABLE t1;
 SHOW COLUMNS FROM t1;
 DROP TABLE t1;
+
+#
+# Bug #6345 Unexpected behaviour with partial indices
+#
+--disable_warnings
+CREATE TABLE t1
+(
+  a INTEGER NOT NULL,
+  b VARCHAR(50) NOT NULL DEFAULT '',
+  PRIMARY KEY  (a),
+  KEY b (b(10))
+) TYPE=InnoDB CHARACTER SET 'ujis' COLLATE 'ujis_japanese_ci';
+--enable_warnings
+INSERT INTO t1 (a, b) VALUES (0, 'aaabbbcccddd');
+INSERT INTO t1 (a, b) VALUES (1, 'eeefffggghhh');
+INSERT INTO t1 (a, b) VALUES (2, 'iiijjjkkkl');
+SELECT t1.* FROM t1 WHERE b='aaabbbcccddd' ORDER BY a;
+SELECT t1.* FROM t1 WHERE b='eeefffggghhh' ORDER BY a;
+SELECT t1.* FROM t1 WHERE b='iiijjjkkkl'   ORDER BY a;
+DROP TABLE t1;
+--disable_warnings
+CREATE TABLE t1
+(
+  a INTEGER NOT NULL,
+  b VARCHAR(50) NOT NULL DEFAULT '',
+  PRIMARY KEY  (a),
+  KEY b (b(10))
+) TYPE=MyISAM CHARACTER SET 'ujis' COLLATE 'ujis_japanese_ci';
+--enable_warnings
+INSERT INTO t1 (a, b) VALUES (0, 'aaabbbcccddd');
+INSERT INTO t1 (a, b) VALUES (1, 'eeefffggghhh');
+INSERT INTO t1 (a, b) VALUES (2, 'iiijjjkkkl');
+SELECT t1.* FROM t1 WHERE b='aaabbbcccddd' ORDER BY a;
+SELECT t1.* FROM t1 WHERE b='eeefffggghhh' ORDER BY a;
+SELECT t1.* FROM t1 WHERE b='iiijjjkkkl'   ORDER BY a;
+DROP TABLE t1;

sql/field.cc

@@ -4401,10 +4401,14 @@ int Field_string::cmp(const char *a_ptr, const char *b_ptr)
                                             (const uchar*) b_ptr,
                                             field_length);
   }
-  return my_strnncoll(field_charset,(const uchar*) a_ptr, field_length,
-                                    (const uchar*) b_ptr, field_length);
+  uint char_len= field_length/field_charset->mbmaxlen;
+  uint a_len= my_charpos(field_charset, a_ptr, a_ptr + field_length, char_len);
+  uint b_len= my_charpos(field_charset, b_ptr, b_ptr + field_length, char_len);
+  return my_strnncoll(field_charset,(const uchar*) a_ptr, a_len,
+                                    (const uchar*) b_ptr, b_len);
 }
 
+
 void Field_string::sort_string(char *to,uint length)
 {
   uint tmp=my_strnxfrm(field_charset,