SET @userstat.save= @@userstat;

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

INSERT INTO t VALUES (1,10),(2,20),(2,21),(3,30),(4,40),(5,50);

SET GLOBAL userstat= 1;

FLUSH INDEX_STATISTICS;

EXPLAIN SELECT * FROM t WHERE a = 2 AND b = 20;

SELECT * FROM t WHERE a = 2 AND b = 20;

SHOW INDEX_STATISTICS;

# Cleanup

DROP TABLE t;

SET GLOBAL userstat= @userstat.save;

EXPLAIN SELECT * FROM t WHERE a = 2 AND b = 20;

id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

1	SIMPLE	t	index_merge	a,b	b,a	5,5	NULL	1	Using intersect(b,a); Using where; Using index

SELECT * FROM t WHERE a = 2 AND b = 20;

a	b

2	20

SHOW INDEX_STATISTICS;

Table_schema	Table_name	Index_name	Rows_read

test	t	b	1

DROP TABLE t;