DROP TABLE IF EXISTS users;
FLUSH STATUS;
CREATE TABLE users (
age INT,
INDEX (age)
) DEFAULT CHARSET=UTF8;
INSERT INTO users (age) VALUES (28);
INSERT INTO users (age) VALUES (28);
INSERT INTO users (age) VALUES (29);
INSERT INTO users (age) VALUES (29);
INSERT INTO users (age) VALUES (29);
explain SELECT COUNT(*) FROM users WHERE age <> 29;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	users	range	age	age	5	NULL	4	Using where; Using index
SELECT COUNT(*) FROM users WHERE age <> 29;
COUNT(*)
2
SHOW STATUS LIKE 'mroonga_count_skip';
Variable_name	Value
Mroonga_count_skip	2
DROP TABLE users;
