[#MDEV-8613] Full table scan for WHERE indexed_varchar

SET NAMES utf8;

DROP TABLE IF EXISTS t1;

CREATE TABLE t1 (a VARCHAR(10) CHARACTER SET utf8, KEY(a)) ENGINE=MyISAM;

INSERT INTO t1 VALUES ('a'),('b'),('c'),('d'),('e');

EXPLAIN SELECT * FROM t1 WHERE a='��';

+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+

| id   | select_type | table | type | possible_keys | key  | key_len | ref  | rows | Extra                                               |

+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+

|    1 | SIMPLE      | NULL  | NULL | NULL          | NULL | NULL    | NULL | NULL | Impossible WHERE noticed after reading const tables |

+------+-------------+-------+------+---------------+------+---------+------+------+-----------------------------------------------------+

[MDEV-8613] Full table scan for WHERE indexed_varchar_column <=> 'bad-character' Created: 2015-08-13 Updated: 2015-08-14 Resolved: 2015-08-13
Status:	Closed
Project:	MariaDB Server
Component/s:	Optimizer
Affects Version/s:	5.5, 10.0, 10.1
Fix Version/s:	10.1.7