ERROR 1205 (HY000): Lock wait timeout exceeded; try restarti

ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

前言：朋友咨询我说执行简单的update语句失效，症状如下：
mysql> update order_info set province_id=15 ,city_id= 1667 where order_from=10 and order_out_sn='1407261241xxxx';
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
mysql>

QQ远程过去，开始check
1，查看数据库的隔离级别：

mysql> select @@tx_isolation;
+-----------------+
| @@tx_isolation |
+-----------------+
| REPEATABLE-READ |
+-----------------+
1 row in set (0.00 sec)

mysql>

2，去查看先当前库的线程情况：

mysql> show full processlist;

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

| Id | User | Host | db | Command | Time | State | Info |

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

| 1 | event_scheduler | localhost | NULL | Daemon | 9635385 | Waiting on empty queue | NULL |