Waiting for table metadata lock问题的解决

session1:
mysql> start transaction ;
Query OK, 0 rows affected (0.00 sec)


mysql> select * from t2;
+----+------+------+------+------+
| id | a    | b    | c    | e    |
+----+------+------+------+------+
|  0 |    0 | NULL |    0 |    0 |
|  1 |    1 |    1 |    1 |    1 |
|  2 |    2 |    1 |    2 |    2 |
|  3 |    3 |    1 |    1 |    3 |
|  4 |    4 |    2 |    1 |    4 |
|  5 |    5 |    2 |    2 |    5 |
|  6 |    6 |    1 |    1 |    6 |
|  7 |    7 |    2 |    2 |    7 |
|  8 |    8 |    3 |    3 |    8 |
|  9 |    9 |    4 |    5 | NULL |
+----+------+------+------+------+
10 rows in set (0.03 sec)


mysql> select * from t3;
+----+------+------+------+------+
| id | a    | b    | c    | e    |
+----+------+------+------+------+
|  0 |    0 | NULL |    0 |    0 |
|  1 |    1 |    1 |    1 |    1 |
|  2 |    2 |    1 |    2 |    2 |
|  3 |    3 |    1 |    1 |    3 |
|  4 |    4 |    2 |    1 |    4 |
|  5 |    5 |    2 |    2 |    5 |
|  6 |    6 |    1 |    1 |    6 |
|  8 |    8 |    3 |    3 |    8 |
|  9 |    9 |    4 |    5 | NULL |
+----+------+------+------+------+
9 rows in set (0.04 sec)


session2:
mysql> drop table t2;


session3:
mysql> show processlist;
+----+------+-----------+------+---------+------+---------------------------------+------------------+
| Id | User | Host      | db   | Command | Time | State                           | Info             |
+----+------+-----------+------+---------+------+---------------------------------+------------------+
|  9 | root | localhost | test | Sleep   |  122 |                                 | NULL             |
| 10 | root | localhost | test | Query   |   49 | Waiting for table metadata lock | drop table t2    |
| 11 | root | localhost | NULL | Query   |    0 | init                            | show processlist |
+----+------+-----------+------+---------+------+---------------------------------+------------------+
3 rows in set (0.01 sec)


session1:
mysql> commit;
Query OK, 0 rows affected (0.00 sec)


session3:
mysql> show processlist;
+----+------+-----------+------+---------+------+-------+------------------+
| Id | User | Host      | db   | Command | Time | State | Info             |
+----+------+-----------+------+---------+------+-------+------------------+
|  9 | root | localhost | test | Sleep   |   30 |       | NULL             |
| 10 | root | localhost | test | Sleep   |  202 |       | NULL             |
| 11 | root | localhost | NULL | Query   |    0 | init  | show processlist |
+----+------+-----------+------+---------+------+-------+------------------+
3 rows in set (0.00 sec)