MySQL Replication Error 处理一例

故障现象

MySQL slave status详情

mysql> show slave status\G
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 10.10.10.101
                Master_User: root
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000010
        Read_Master_Log_Pos: 143861468
             Relay_Log_File: slave-relay-bin.000525
              Relay_Log_Pos: 128835579
      Relay_Master_Log_File: mysql-bin.000010
           Slave_IO_Running: Yes
          Slave_SQL_Running: No
            Replicate_Do_DB:
        Replicate_Ignore_DB:
         Replicate_Do_Table:
     Replicate_Ignore_Table:
    Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table: mysql.%,information_schema.%,test.%
                 Last_Errno: 0
                 Last_Error: Could not parse relay log event entry. The possck this by running ‘mysqlbinlog‘ on the binary log), the slave‘s relay log iay log), a network problem, or a bug in the master‘s or slave‘s MySQL code. you will be able to know their names by issuing ‘SHOW SLAVE STATUS‘ on this
               Skip_Counter: 0
        Exec_Master_Log_Pos: 128835442
            Relay_Log_Space: 143862393
            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
1 row in set (0.00 sec)

mysql> 

MySQL 错误日志中显示了问题的根源,磁盘空间满.

thatsit-mysql:/var/lib/mysql # grep -i disk mysqld.log-20160114
/usr/sbin/mysqld: Disk is full writing ‘./mysql-bin.000319‘ (Errcode: 28). Waiting for someone to free space... (Expect up to 60 secs delay for server to continue after freeing disk space)
/usr/sbin/mysqld: Disk is full writing ‘./mysql-bin.000320‘ (Errcode: 28). Waiting for someone to free space... (Expect up to 60 secs delay for server to continue after freeing disk space)
thatsit-mysql:/var/lib/mysql # 

MySQL 错误日志中同样还记录了binlog执行截至的位置点.

thatsit-mysql:/var/lib/mysql # grep ERROR mysqld.log-20160114|grep stopped|tail -1
160114 13:16:16 [ERROR] Error running query, slave SQL thread aborted. Fix the problem, and restart the slave SQL thread with "SLAVE START". We stopped at log ‘mysql-bin.000010‘ position 128835442
thatsit-mysql:/var/lib/mysql # 

修复

① 清理MySQL datadir所在的磁盘

② 恢复MySQL SLAVE (STOP SLAVE → CHANGE MASTER → START SLAVE)

※: 位置点为上面从SLAVE STATUS的"Exec_Master_Log_Pos"或者错误日志中获取的.

mysql> stop slave;
Query OK, 0 rows affected (0.00 sec)

mysql>
mysql> CHANGE MASTER TO
    -> MASTER_HOST=‘10.10.10.101‘,
    -> MASTER_PORT=3306,
    -> MASTER_USER=‘REP_USER‘,
    -> MASTER_PASSWORD=‘REP_PASSWORD‘,
    -> MASTER_LOG_FILE=‘mysql-bin.000010‘,
    -> MASTER_LOG_POS=128835442;
Query OK, 0 rows affected (0.41 sec)

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql>

操作后状态确认

mysql> show slave status\G
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 10.10.10.101
                Master_User: root
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000010
        Read_Master_Log_Pos: 144444705
             Relay_Log_File: slave-relay-bin.000002
              Relay_Log_Pos: 38259
      Relay_Master_Log_File: mysql-bin.000010
           Slave_IO_Running: Yes
          Slave_SQL_Running: Yes
            Replicate_Do_DB:
        Replicate_Ignore_DB:
         Replicate_Do_Table:
     Replicate_Ignore_Table:
    Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table: mysql.%,information_schema.%,test.%
                 Last_Errno: 0
                 Last_Error:
               Skip_Counter: 0
        Exec_Master_Log_Pos: 128873466
            Relay_Log_Space: 15609498
            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: 99299
1 row in set (0.00 sec)

mysql>

此故障至此修复完毕.