-- Reproduced with 5.5.17, but not with 5.5.28

DROP TABLE IF EXISTS countbug;
CREATE TABLE countbug (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `ts1` timestamp NULL DEFAULT NULL,
  `ts2` timestamp NULL DEFAULT NULL,
  PRIMARY KEY (`id`),
  KEY `ts1` (`ts1`),
  KEY `ts2` (`ts2`)
) ENGINE=InnoDB;

DELIMITER //

DROP PROCEDURE IF EXISTS countbug_fill //
CREATE PROCEDURE countbug_fill(IN rowCount INT UNSIGNED)
BEGIN
    SET @i = 0;
    START TRANSACTION;
    REPEAT
        INSERT INTO countbug (ts1) VALUES (NULL);
        SET @i = @i + 1;
    UNTIL @i >= rowCount END REPEAT;
    COMMIT;
END //

DELIMITER ;

-- Incorrect composite index behaviour only appears with enough rows
CALL countbug_fill(300000);

SELECT SQL_NO_CACHE COUNT(*) FROM countbug WHERE ts1 IS NULL OR ts2 IS NULL;

-- Adding index "on the fly" causes composite index to return invalid value
ALTER TABLE countbug ADD KEY `ts1ts2` (`ts1`,`ts2`);
SELECT SQL_NO_CACHE COUNT(*) FROM countbug WHERE ts1 IS NULL OR ts2 IS NULL;
SELECT SQL_NO_CACHE COUNT(*) FROM countbug IGNORE INDEX (`ts1ts2`) WHERE ts1 IS NULL OR ts2 IS NULL;

-- Rebuilding table causes problem too disappear
OPTIMIZE TABLE countbug;
SELECT SQL_NO_CACHE COUNT(*) FROM countbug WHERE ts1 IS NULL OR ts2 IS NULL;