MySQL从库报Error_code: 2005

创建MySQL主从复制过程中，change master之后，启动slave复制，发现从库状态不正常。报如下错误：

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mysql> show slave status\G *************************** 1. row ***************************                Slave_IO_State: Connecting to master                   Master_Host: abcedeawstest-instance-7.chedandeheny.ap-northeast-7.rds.ama                   Master_User: repl                   Master_Port: 3336                 Connect_Retry: 60               Master_Log_File: mysql-bin-changelog.000009           Read_Master_Log_Pos: 60349807                Relay_Log_File: relay-bin.000001                 Relay_Log_Pos: 4         Relay_Master_Log_File: mysql-bin-changelog.000009              Slave_IO_Running: Connecting             Slave_SQL_Running: Yes               Replicate_Do_DB:           Replicate_Ignore_DB:            Replicate_Do_Table:        Replicate_Ignore_Table:       Replicate_Wild_Do_Table:   Replicate_Wild_Ignore_Table:                    Last_Errno: 0                    Last_Error:                  Skip_Counter: 0           Exec_Master_Log_Pos: 60349807               Relay_Log_Space: 154               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: 2005                 Last_IO_Error: error connecting to master 'repl@abcedeawstest-instance-7.chedandeheny.ap-northeast-7.rds.ama:3336' - retry-time: 60  retries: 1                Last_SQL_Errno: 0                Last_SQL_Error:   Replicate_Ignore_Server_Ids:              Master_Server_Id: 0                   Master_UUID:              Master_Info_File: /data/master.info                     SQL_Delay: 0           SQL_Remaining_Delay: NULL       Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates            Master_Retry_Count: 86400                   Master_Bind:       Last_IO_Error_Timestamp: 211116 11:40:02      Last_SQL_Error_Timestamp:                Master_SSL_Crl:            Master_SSL_Crlpath:            Retrieved_Gtid_Set:             Executed_Gtid_Set:                 Auto_Position: 0          Replicate_Rewrite_DB:                  Channel_Name:            Master_TLS_Version: 1 row in set (0.00 sec)   mysql>

　　

这里的错误编码是2005：

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Error number: 2005; Symbol: CR_UNKNOWN_HOST;   Message: Unknown MySQL server host '%s' (%d)

　　

原因：
主机的主机域名太长。全称是：

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1	abcedeawstest-instance-7.chedandeheny.ap-northeast-7.rds.amazonaws.com

　　

长度超过了60个字符，被截取成了：

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1	abcedeawstest-instance-7.chedandeheny.ap-northeast-7.rds.ama

从而变成了一个不正确的主机名。这一点从show slave status的输出结果就可以看出。

 

解决方案：
将域名改成了服务器的IP地址,重新建立与主库的连接。