由于系统突然死机，重启之后mysql报关于 relay log 的错误
错误如下：
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: xx.xx.xx.xx
Master_User: xxxxxx
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: bin-update-log.000189
Read_Master_Log_Pos: 298793095
Relay_Log_File: mysqld-relay-bin.000384
Relay_Log_Pos: 76947288
Relay_Master_Log_File: bin-update-log.000189
Slave_IO_Running: Yes
Slave_SQL_Running: No
Replicate_Do_DB: xx,xx
Replicate_Ignore_DB: local
Replicate_Do_Table:
Replicate_Ignore_Table: xx._tmp_so6,xx._tmp_so6
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1594
Last_Error: Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master's binary log is corrupted (you can check this by running 'mysqlbinlog' on the binary log), the slave's relay log is corrupted (you can check this by running 'mysqlbinlog' on the relay log), a network problem, or a bug in the master's or slave's MySQL code. If you want to check the master's binary log or slave's relay log, you will be able to know their names by issuing 'SHOW SLAVE STATUS' on this slave.
这个replication错误，不能用
GLOBAL sql_slave_skip_counter 跳过，而是因为relay log crashed，这个时候就需要找到slave 主机上面crash之前的那个position，然后对应的在master 上面的binlog 里面找到对应的点 ，然后再slave上面reset slave，重新配置master链接信息就好
关键在于在到crash之前的点
Relay_Log_File: mysqld-relay-bin.000384
Relay_Log_Pos: 76947288
检查relay log，找到如下位置
# at 76947261
#140227 3:33:15 server id 259 end_log_pos 76947137 Xid = 2827563451
COMMIT/*!*/;
# at 76947288
#140227 3:33:15 server id 259 end_log_pos 76947216 Query thread_id=21165454 exec_time=0 error_code=0
SET TIMESTAMP=1393443195/*!*/;
BEGIN
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
找到位置： 76947216 ;
在master上面找到这个点和对应的文件
bin-update-log.000189
# at 76947216
#140227 3:33:15 server id 259 end_log_pos 76947505 Query thread_id=21165454 exec_time=0 error_code=0
SET TIMESTAMP=1393443195/*!*/;
在slave上面处理
mysql> stop slave ;
Query OK, 0 rows affected (0.00 sec)
mysql> reset slave ;
Query OK, 0 rows affected (0.12 sec)
mysql> change master to master_user ='xxxxxxx',master_host='xx.xx.xx.xx',master_password='xx.xxxx',master_log_file='bin-update-log.000189',master_log_pos=76947216;
Query OK, 0 rows affected (0.00 sec)
mysql> start slave ;
Query OK, 0 rows affected (0.00 sec)
然后show slave status ,此时整个slave显示正常
