主从架构。今天发现从库SQL线程报错，主从复制停止了。查看错误发现：
Last_SQL_Errno: 1205
Last_SQL_Error: Slave SQL thread retried transaction 10 time(s) in vain, giving up. Consider raising the value of the slave_transaction_retries variable.
查看错误日志发现：
2016-05-25 07:27:09 72865 [Warning] Slave SQL: Could not execute Write_rows event on table xxx.xxx; Lock wait timeout exceeded; try restarting transaction, Error_code:
1205; handler error HA_ERR_LOCK_WAIT_TIMEOUT; the event's master log mysql-bin.000121, end_log_pos 21432849, Error_code: 1205
2016-05-25 07:27:09 72865 [ERROR] Slave SQL: Slave SQL thread retried transaction 10 time(s) in vain, giving up. Consider raising the value of the slave_transaction_retries variable. Error_code: 1205
2016-05-25 07:27:09 72865 [Warning] Slave: Lock wait timeout exceeded; try restarting transaction Error_code:1205
2016-05-25 07:27:09 72865 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log 'mysql-bin.000121' position 21432467
解决办法：
start slave;
原因：
是MySQL的一个bug，可以考虑把patch给打上