drop、delete、truncate、alter表时show processlist出现Waiting for table metadata lock状态

drop、delete、truncate、alter表时show processlist出现Waiting for table metadata lock状态

一个一百多行的表执行drop、delete、truncate、alter表时一直处于等待状态

这种情况一定是存在锁，事务没提交

MySQL> select trx_id,trx_mysql_thread_id from information_schema.INNODB_TRX;

+-----------------+---------------------+

| trx_id          | trx_mysql_thread_id |

+-----------------+---------------------+

| 79447           |                1012 |
| 421181791813712 |                  28 |

| 421181791799120 |                  12 |

+-----------------+---------------------+

3 rows in set (0.01 sec)

mysql> select trx_id,trx_mysql_thread_id from information_schema.INNODB_TRX;

+-----------------+---------------------+

| trx_id          | trx_mysql_thread_id |

+-----------------+---------------------+

| 79447           |                1012 |

| 421181791813712 |                  28 |

| 421181791799120 |                  12 |

+-----------------+---------------------+

3 rows in set (0.01 sec)

mysql> kill 28;

Query OK, 0 rows affected (0.00 sec)

mysql> kill 12;

Query OK, 0 rows affected (0.00 sec)

mysql> select trx_id,trx_mysql_thread_id from information_schema.INNODB_TRX;

+-----------------+---------------------+

| trx_id          | trx_mysql_thread_id |

+-----------------+---------------------+

| 79447           |                1012 |

+-----------------+---------------------+

1 rows in set (0.01 sec)

再执行该表的drop delete truncate操作没问题了