Mysql – How to skip the current ‘Relay_Master_Log_File’ in AWS MYSQL RDS

amazon-rdsawsMySQLreplication

Below is the status of my slave. The master log file is at position "mysql-bin-changelog.278337" but the slave log file is at position "mysql-bin-changelog.278008". How to skip the current executing "Relay_Master_Log_File" t point to some other log file?

    mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: kdm-eink-prod.cfewehpmjefz.us-east-1.rds.amazonaws.com
                  Master_User: rdsrepladmin
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin-changelog.278337
          Read_Master_Log_Pos: 120
               Relay_Log_File: relaylog.377536
                Relay_Log_Pos: 1148
        Relay_Master_Log_File: mysql-bin-changelog.278008
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: mysql.plugin,mysql.rds_monitor,mysql.rds_sysinfo,mysql.rds_replication_status,mysql.rds_history,innodb_memcache.config_options,innodb_memcache.cache_policies
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 975
              Relay_Log_Space: 354792434
              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: 98230
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: 1113717901
                  Master_UUID: ec0eef96-a6e9-11e2-bdf0-0015174ecc8e
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Sending data
           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 (0.24 sec)

ERROR: 
No query specified

Best Answer

Replication Lag is usually measured by finding the difference between the following

  • TIMESTAMP#1 at (Relay_Master_Log_File,Exec_Master_Log_Pos)
  • TIMESTAMP#2 at (Master_Log_File,Read_Master_Log_Pos)

From what I am seeing in the SHOW SLAVE STATUS\G

  • you are 98230 seconds (27 hours 17 minutes 10 seconds) behind
  • you have 329 binlogs (278337 - 278008) to process after mysql-bin-changelog.278337
  • The sum of all your binlogs is 354792434 (338M)

If the Seconds_Behind_Master is steadily increasing by one every second, you will have to wait it out and let replication catch up. This is a strange indication that you are running some terrible query that is making the number of binlogs waiting to be processed increase. You could see that query by running show processlist; and look for the SQL thread (where the user is system user) with the same number for Time as the Seconds_Behind_Master.

If you cannot wait for the catch up of replication, you just need to spin up another read-only slave and drop this very latent slave.

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