mysql5.6主从复制日志应用错误

今天做主从测试，在从库进行日志应用的时候报了一个错，导致从库的slave IO sql应用进程停止工作，报了一个下面的错：

mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 127.0.0.1
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000018
Read_Master_Log_Pos: 2807
Relay_Log_File: relaylog.000002
Relay_Log_Pos: 1279
Relay_Master_Log_File: binlog.000018
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:
Last_Errno: 1141
Last_Error: Error 'There is no such grant defined for user 'wufan' on host '%'' on query. Default database: 'test'. Query: 'revoke SELECT ON `jfedu`.* from wufan@'%''
Skip_Counter: 0
Exec_Master_Log_Pos: 1717
Relay_Log_Space: 3656
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: 1141
Last_SQL_Error: Error 'There is no such grant defined for user 'wufan' on host '%'' on query. Default database: 'test'. Query: 'revoke SELECT ON `jfedu`.* from wufan@'%''
Replicate_Ignore_Server_Ids:
Master_Server_Id: 101
Master_UUID: 36020f29-004a-11e8-9f6a-080027293866
Master_Info_File: /u01/my3307/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: 180203 18:05:22
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)

ERROR:
No query specified

1，在主库上执行了revoke all privileges on *.* from wufan@'%' ;

2，从库同时也会执行这样语句，但是由于从库并没有wufan这个用户，所以必然报错

可以看到，从主库复制binlog的salve_io线程还在忙活，但是执行从库更新的slave_sql已经罢工了，从Last_error:可以看到是因为执行主库执行跟wufan用户相关的权限操作时报的错。

There is no such grant defined for user 'wufan' on host '%'' on query. Default database: 'test'. Query: 'revoke SELECT ON `jfedu`.* from wufan@'%''

此时可以通过使从库跳过这一错误事件继续运行下面的日志应用：

mysql> set global sql_slave_skip_counter=1;
Query OK, 0 rows affected (0.00 sec)

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

上面的语句是告诉slave跳过当前卡住的event，然后重新起来干活。

查看一下slave的状态：

mysql> show slave status \G;
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 127.0.0.1
Master_User: repl
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: binlog.000018
Read_Master_Log_Pos: 2807
Relay_Log_File: relaylog.000006
Relay_Log_Pos: 280
Relay_Master_Log_File: binlog.000018
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: 2807
Relay_Log_Space: 606
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: 0
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: 101
Master_UUID: 36020f29-004a-11e8-9f6a-080027293866
Master_Info_File: /u01/my3307/data/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
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)

ERROR:
No query specified

注意这两个信息：

Slave_IO_Running: Yes
Slave_SQL_Running: Yes

发现日志获取io进程和sql应用进程都正常了。

上面的方法在slave比较少的时候还可以，但是当从库有几十台时，逐台去处理既费时又容易出错，怎样在主库这一侧一劳永逸地避免呢？

对，就是在主库这侧不要将这样的grant语句写入到binlog中，MySQL不愧世界级的软件产品，它提供了一个session粒度的选项，通过关闭这个选项可以不让主库将打开这个选项或关闭连接前的SQL语句写入binlog。

在主库侧执行下面的命令临时关闭binlog日志，然后需要的时候在启动binlog日志