Comment 1 for bug 1646880

I was able to break the ascending order by using the same table:

CREATE TABLE `sorting` (
  `id` int(11) unsigned NOT NULL,
  `data` varchar(10) DEFAULT NULL,
  KEY `data_idx` (`data`(2),`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
/*!50100 PARTITION BY RANGE (`id`)
(PARTITION p10 VALUES LESS THAN (10) ENGINE = InnoDB,
 PARTITION p20 VALUES LESS THAN (20) ENGINE = InnoDB) */;

and the same initial inserts:

INSERT INTO `sorting` VALUES
 (9,'aa2'),
 (11,'aa2'),
 (12,'aa2')
;

but a different final insert:

INSERT INTO `sorting` VALUES (9,'aa3');

Now query the table:

SELECT id FROM sorting WHERE data = 'aa2' ORDER BY id ASC;

The following result shows up:

+----+
| id |
+----+
| 11 |
| 12 |
| 9 |
+----+

Strangely enough, removing the order by actually gives the correctly ordered result:

SELECT id FROM sorting WHERE data = `aa2`;

+----+
| id |
+----+
| 9 |
| 11 |
| 12 |
+----+