Wrong result upon LEFT JOIN and NULL comparison with not_null_range_scan

CREATE TABLE t1 (a INT, b INT) ENGINE=MyISAM;

INSERT INTO t1 VALUES  (10,1),(null,2);

CREATE TABLE t2 (pk INT PRIMARY KEY) ENGINE=MyISAM;

INSERT INTO t2 VALUES (1),(2);

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

SET optimizer_switch= 'not_null_range_scan=on';

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

DROP TABLE t1, t2;

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

b

2

SET optimizer_switch= 'not_null_range_scan=on';

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

b

DROP TABLE t1, t2;

explain extended SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using filesort

Warnings:

Note	1003	select `test`.`t1`.`b` AS `b` from `test`.`t1` where `test`.`t1`.`a` is null order by `test`.`t1`.`b`

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

b

2

SET optimizer_switch= 'not_null_range_scan=on';

SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

b

explain extended SELECT t1.b FROM t1 LEFT JOIN t2 ON t1.a = t2.pk WHERE t1.a IS NULL ORDER BY t1.b;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra

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

Warnings:

Note	1003	select `test`.`t1`.`b` AS `b` from `test`.`t1` where 0 order by `test`.`t1`.`b`