由於系統突然死機，重啓之後mysql報錯如下：
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.
這個錯誤一般的replication錯誤，不能用
GLOBAL sql_slave_skip_counter 跳過，而是因爲relay log crashed，這個時候就需要找到slave 主機上面crash之前的那個position，然後對應的在master 上面的binlog 裏面找到對應的點 ，然後再slave上面reset slave，重新配置master鏈接信息就好
1，關鍵在於在到crash之前的點，
Relay_Log_File: mysqld-relay-bin.000384
Relay_Log_Pos: 76947288
check this relay log and find :
# 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*/;
so the important point is 76947216 ;
2,在master上面找到這個點和對應的文件
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/*!*/;
3 ，在slave上面處理
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)
然後show slave status ,此時整個slave顯示正常