mysql从站一直卡在从中继日志中读取事件

Question

前两天，我在master上通过“source xxx.sql”导入数据，有135万行记录，总大小10G，执行导入操作后master一切正常。但是master上已经完成了两天了，slave的状态仍然是“Reading event from the relay log”，谁能帮我解决这个问题？先谢谢了。

以下是有关从属状态的详细信息:

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.1.50
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.001137
          Read_Master_Log_Pos: 43132410
               Relay_Log_File: mysql-relay-bin.002897
                Relay_Log_Pos: 497809898
        Relay_Master_Log_File: mysql-bin.001130
             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: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 497809685
              Relay_Log_Space: 40113924576
              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: 161225
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: 1
                  Master_UUID: 0f9e9ec5-ed9f-11e5-9a4a-525400c50c20
             Master_Info_File: /data/mysql1/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Reading event from the relay log
           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
         Replicate_Rewrite_DB: 
                 Channel_Name: 
           Master_TLS_Version: 
1 row in set (0.00 sec)

以下是从站上的中继日志列表:

-rw-r----- 1 mysql mysql  254 Oct 15 11:17 mysql-relay-bin.002896
-rw-r----- 1 mysql mysql  19G Oct 15 11:40 mysql-relay-bin.002897
-rw-r----- 1 mysql mysql 161K Oct 15 11:40 mysql-relay-bin.002898
-rw-r----- 1 mysql mysql  254 Oct 15 11:40 mysql-relay-bin.002899
-rw-r----- 1 mysql mysql  67M Oct 15 12:10 mysql-relay-bin.002900
-rw-r----- 1 mysql mysql  18G Oct 15 12:14 mysql-relay-bin.002901
-rw-r----- 1 mysql mysql 112K Oct 15 12:14 mysql-relay-bin.002902
-rw-r----- 1 mysql mysql  254 Oct 15 12:14 mysql-relay-bin.002903
-rw-r----- 1 mysql mysql  420 Oct 15 12:14 mysql-relay-bin.002904
-rw-r----- 1 mysql mysql 4.4M Oct 15 12:14 mysql-relay-bin.002905
-rw-r----- 1 mysql mysql  254 Oct 15 12:14 mysql-relay-bin.002906
-rw-r----- 1 mysql mysql  420 Oct 15 12:14 mysql-relay-bin.002907
-rw-r----- 1 mysql mysql  254 Oct 15 12:14 mysql-relay-bin.002908
-rw-r----- 1 mysql mysql 122M Oct 15 14:34 mysql-relay-bin.002909
-rw-r----- 1 mysql mysql  207 Oct 15 14:34 mysql-relay-bin.002910
-rw-r----- 1 mysql mysql 7.9M Oct 15 15:27 mysql-relay-bin.002911
-rw-r----- 1 mysql mysql  207 Oct 15 15:27 mysql-relay-bin.002912
-rw-r----- 1 mysql mysql 371K Oct 15 15:34 mysql-relay-bin.002913
-rw-r----- 1 mysql mysql  207 Oct 15 15:34 mysql-relay-bin.002914
-rw-r----- 1 mysql mysql  76M Oct 15 23:00 mysql-relay-bin.002915
-rw-r----- 1 mysql mysql 5.3M Oct 15 23:59 mysql-relay-bin.002916
-rw-r----- 1 mysql mysql  254 Oct 15 23:59 mysql-relay-bin.002917
-rw-r----- 1 mysql mysql  36M Oct 16 08:05 mysql-relay-bin.002918
-rw-r----- 1 mysql mysql 4.4M Oct 16 08:22 mysql-relay-bin.002919
-rw-r----- 1 mysql mysql 979M Oct 16 23:00 mysql-relay-bin.002920
-rw-r----- 1 mysql mysql 5.5M Oct 16 23:58 mysql-relay-bin.002921
-rw-r----- 1 mysql mysql  254 Oct 16 23:58 mysql-relay-bin.002922
-rw-r----- 1 mysql mysql  38M Oct 17 08:02 mysql-relay-bin.002923
-rw-r----- 1 mysql mysql 6.6M Oct 17 08:53 mysql-relay-bin.002924
-rw-r----- 1 mysql mysql  725 Oct 17 08:02 mysql-relay-bin.index

Answer 1

查看Seconds_Behind_Master:161225从站状态输出中的线路，目前延迟为 44 小时。

运行show Slave status几次并对其变化率提出建议，如果一切正常，它应该不断下降。

为了加快从服务器的速度，您可以减少服务器上的负载:停止查询一段时间并停止服务器上发生的任何其他事件。

但是，您可能会发现从主站的新鲜转储中重置从站是合理的，percona 的 xtrabackup 可以在不锁定数据库的情况下完成此操作(除非您经常使用 MyISAM，因为它最适合 innodb 引擎)。