Fixed bug #16674.

The length of the prefix of the pattern string in the LIKE predicate that 
determined the index range to be scanned was calculated incorrectly for
multi-byte character sets. 
As a result of this in 4. 1 the the scanned range was wider then necessary
if the prefix contained not only one-byte characters.  
In 5.0 additionally it caused missing some rows from the result set.


mysql-test/r/ctype_utf8.result:
  Added test cases for bug #16674.
mysql-test/t/ctype_utf8.test:
  Added test cases for bug #16674.
strings/ctype-mb.c:
  Fixed bug #16674.
  The length of the prefix of the pattern string in the LIKE predicate that 
  determined the index range to be scanned was calculated incorrectly for
  multi-byte character sets. 
  As a result of this in 4. 1 the the scanned range was wider then necessary
  if the prefix contained not only one-byte characters.  
  In 5.0 additionally it caused missing some rows from the result set.
      
  The function my_like_range_mb was fixed to calculate the length of
  the prefix in a pattern string correctly in all cases.

2 files changed, 122 insertions, 0 deletions

diff --git a/mysql-test/r/ctype_utf8.result b/mysql-test/r/ctype_utf8.result
index 69d7577ee77..dff4476993c 100644
--- a/mysql-test/r/ctype_utf8.result
+++ b/mysql-test/r/ctype_utf8.result
@@ -1124,3 +1124,70 @@ check table t1;
 Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 drop table t1;
+SET NAMES utf8;
+CREATE TABLE t1 (
+a CHAR(13) DEFAULT '',
+INDEX(a)
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES 
+('Käli Käli 2-4'), ('Käli Käli 2-4'),
+('Käli Käli 2+4'), ('Käli Käli 2+4'),
+('Käli Käli 2-6'), ('Käli Käli 2-6');
+CREATE TABLE t2 (
+a CHAR(13) DEFAULT '',
+INDEX(a)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
+INSERT INTO t2 VALUES
+('Kali Kali 2-4'), ('Kali Kali 2-4'),
+('Kali Kali 2+4'), ('Kali Kali 2+4'),
+('Kali Kali 2-6'), ('Kali Kali 2-6');
+SELECT a FROM t1 WHERE a LIKE 'Käli Käli 2+4';
+a
+Käli Käli 2+4
+Käli Käli 2+4
+SELECT a FROM t2 WHERE a LIKE 'Kali Kali 2+4';
+a
+Kali Kali 2+4
+Kali Kali 2+4
+EXPLAIN SELECT a FROM t1 WHERE a LIKE 'Käli Käli 2+4';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	a	a	40	NULL	2	Using where; Using index
+EXPLAIN SELECT a FROM t1 WHERE a = 'Käli Käli 2+4';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ref	a	a	40	const	2	Using where; Using index
+EXPLAIN SELECT a FROM t2 WHERE a LIKE 'Kali Kali 2+4';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	range	a	a	14	NULL	2	Using where; Using index
+EXPLAIN SELECT a FROM t2 WHERE a = 'Kali Kali 2+4';
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	ref	a	a	14	const	2	Using where; Using index
+DROP TABLE t1,t2;
+CREATE TABLE t1 (
+a char(255) DEFAULT '', 
+KEY(a(10))
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+a
+Käli Käli 2-4
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+a
+Käli Käli 2-4
+Käli Käli 2-4
+DROP TABLE t1;
+CREATE TABLE t1 (
+a char(255) DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+a
+Käli Käli 2-4
+Käli Käli 2-4
+ALTER TABLE t1 ADD KEY (a(10));
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+a
+Käli Käli 2-4
+Käli Käli 2-4
+DROP TABLE t1;
diff --git a/mysql-test/t/ctype_utf8.test b/mysql-test/t/ctype_utf8.test
index 5044f7979f1..47436956354 100644
--- a/mysql-test/t/ctype_utf8.test
+++ b/mysql-test/t/ctype_utf8.test
@@ -926,4 +926,59 @@ INSERT INTO t1 VALUES('uUABCDEFGHIGKLMNOPRSTUVWXYZ̈bbbbbbbbbbbbbbbbbbbbbbbbbbbb
 check table t1;
 drop table t1;
 
+#
+# Bug#16674: LIKE predicate for a utf8 character set column
+#
+
+SET NAMES utf8;
+
+CREATE TABLE t1 (
+  a CHAR(13) DEFAULT '',
+  INDEX(a)
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES 
+ ('Käli Käli 2-4'), ('Käli Käli 2-4'),
+ ('Käli Käli 2+4'), ('Käli Käli 2+4'),
+ ('Käli Käli 2-6'), ('Käli Käli 2-6');
+
+CREATE TABLE t2 (
+  a CHAR(13) DEFAULT '',
+  INDEX(a)
+) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci;
+
+INSERT INTO t2 VALUES
+ ('Kali Kali 2-4'), ('Kali Kali 2-4'),
+ ('Kali Kali 2+4'), ('Kali Kali 2+4'),
+ ('Kali Kali 2-6'), ('Kali Kali 2-6');
+
+SELECT a FROM t1 WHERE a LIKE 'Käli Käli 2+4';
+SELECT a FROM t2 WHERE a LIKE 'Kali Kali 2+4';
+
+EXPLAIN SELECT a FROM t1 WHERE a LIKE 'Käli Käli 2+4';
+EXPLAIN SELECT a FROM t1 WHERE a = 'Käli Käli 2+4';
+EXPLAIN SELECT a FROM t2 WHERE a LIKE 'Kali Kali 2+4';
+EXPLAIN SELECT a FROM t2 WHERE a = 'Kali Kali 2+4';
+
+DROP TABLE t1,t2;
+
+CREATE TABLE t1 (
+  a char(255) DEFAULT '', 
+  KEY(a(10))
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+DROP TABLE t1;
+
+CREATE TABLE t1 (
+  a char(255) DEFAULT ''
+) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci;
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+INSERT INTO t1 VALUES ('Käli Käli 2-4');
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+ALTER TABLE t1 ADD KEY (a(10));
+SELECT * FROM t1 WHERE a LIKE 'Käli Käli 2%';
+DROP TABLE t1;
+
 # End of 4.1 tests