MySQL5.6从库修改主机名同步停止的解决办法

环境：MySQL5.6 + CentOS6.5

问题描述：从库修改主机名后，从库的同步没有自动启动，用start slave命令开启失败

从库修改主机名后，从库的同步没有自动启动，查看状态如下：

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: 
                  Master_Host: 192.168.1.2
                  Master_User: manager_slave
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: logbin.000053
          Read_Master_Log_Pos: 588641410
               Relay_Log_File: zzstep-relay-bin.000015
                Relay_Log_Pos: 38778474
        Relay_Master_Log_File: logbin.000053
             Slave_IO_Running: No
            Slave_SQL_Running: No
              Replicate_Do_DB: 
          Replicate_Ignore_DB: mysql,information_schema,performance_schema
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: hn.sphinx%
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 588641410
              Relay_Log_Space: 0
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 0
                  Master_UUID: 8ce09c46-a7be-11e4-8e06-0050569f4b5b
             Master_Info_File: /opt/mysql_data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: 
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)

使用start slave命令开启失败：

mysql> start slave;
ERROR 1872 (HY000): Slave failed to initialize relay log info structure from the repository

使用reset slave命令解决：

mysql> reset slave;
Query OK, 0 rows affected (0.01 sec)

mysql> start slave;
Query OK, 0 rows affected (0.03 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Queueing master event to the relay log
                  Master_Host: 192.168.1.2
                  Master_User: manager_slave
                  Master_Port: 3306
                Connect_Retry: 10
              Master_Log_File: logbin.000021
          Read_Master_Log_Pos: 11215004
               Relay_Log_File: db_mysql_02-relay-bin.000007
                Relay_Log_Pos: 22097
        Relay_Master_Log_File: logbin.000005
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: mysql,information_schema,performance_schema
           Replicate_Do_Table: 
       Replicate_Ignore_Table: 
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: hn.sphinx%
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 21937
              Relay_Log_Space: 13113813
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: 1071515
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 11
                  Master_UUID: 8ce09c46-a7be-11e4-8e06-0050569f4b5b
             Master_Info_File: /opt/mysql_data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: creating table
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0
1 row in set (0.00 sec)
mysql>

总结：

由于修改主机名后，relay-log的名称发生变化，导致文件IO失败，reset slave可以重新定位。