mysql: 意外な挙動

term.txt

mysql> show create table m\G
*************************** 1. row ***************************
       Table: m
Create Table: CREATE TABLE `m` (
  `id` int(11) NOT NULL,
  `status` varchar(64) DEFAULT NULL,
  `value` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

mysql> select * from m;
+----+--------+-------+
| id | status | value |
+----+--------+-------+
|  1 | new    |   111 |
|  2 | new    |   111 |
|  3 | new    |   111 |
|  4 | new    |   111 |
|  5 | new    |   111 |
|  6 | new    |   111 |
| 12 | new    |   111 |
|  7 | new    |   111 |
|  8 | new    |   111 |
|  9 | new    |   111 |
| 10 | new    |   111 |
| 11 | new    |   111 |
+----+--------+-------+
12 rows in set (0.00 sec)

mysql> delete from m where id = 12;
Query OK, 1 row affected (0.22 sec)

mysql> insert into m values(12, 'new',  111),(13, 'new',  111),(14, 'new',  111),(15, 'new',  111),(16, 'new',  111),(17, 'new',  111),(18, 'new',  111),(19, 'new',  111),(20, 'new',  111);
Query OK, 9 rows affected (0.00 sec)
Records: 9  Duplicates: 0  Warnings: 0

mysql> select * from m;
+----+--------+-------+
| id | status | value |
+----+--------+-------+
|  1 | new    |   111 |
|  2 | new    |   111 |
|  3 | new    |   111 |
|  4 | new    |   111 |
|  5 | new    |   111 |
|  6 | new    |   111 |
| 12 | new    |   111 |
|  7 | new    |   111 |
|  8 | new    |   111 |
|  9 | new    |   111 |
| 10 | new    |   111 |
| 11 | new    |   111 |
| 13 | new    |   111 |
| 14 | new    |   111 |
| 15 | new    |   111 |
| 16 | new    |   111 |
| 17 | new    |   111 |
| 18 | new    |   111 |
| 19 | new    |   111 |
| 20 | new    |   111 |
+----+--------+-------+
20 rows in set (0.00 sec)