服务器异常导致数据库日志异常，同步失败

解决方法：
登录数据库后通过show slave status\G命令查看 Relay_Master_Log_File 和 Exec_Master_Log_Pos两个参数确定日志同步失败的位置, 重新配置主从同步即可，命令如下：

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql> reset slave all;
Query OK, 0 rows affected (0.06 sec)

mysql> change master to master_host='XXX.XX.X.X',master_port=3306,master_user='root',master_password='XXXXXXX', master_log_file='mysql-bin.000055',master_log_pos=129546374;
Query OK, 0 rows affected, 2 warnings (0.02 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Queueing master event to the relay log