状况描述：
今天登录一个MySQL数据库slave节点主机发现/var/lib/mysql下存放大量的mysql-relay-bin文件，最早的文件创建日期甚至是2018年，我记得在slave库同步完master的日志操作记录后，会删除这些文件（默认设置不会删除，我记错了），于是便查看了slave库的状态，发现如下报错：
mysql show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: *.*.*.* Master_User: dbsync Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mysql-bin.000095 Read_Master_Log_Pos: 869242147 Relay_Log_File: mysqld-relay-bin.000146 Relay_Log_Pos: 871280529 Relay_Master_Log_File: mysql-bin.000075 Slave_IO_Running: Yes Slave_SQL_Running: No Replicate_Do_DB: cdb,cdb_admin Replicate_Ignore_DB: mysql Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 1594 Last_Error: Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master's binary log is corrupted (you can check this by running 'mysqlbinlog' on the binary log), the slave's relay log is corrupted (you can check this by running 'mysqlbinlog' on the relay log), a network problem, or a bug in the master's or slave's MySQL code. If you want to check the master's binary log or slave's relay log, you will be able to know their names by issuing 'SHOW SLAVE STATUS' on this slave. Skip_Counter: 0 Exec_Master_Log_Pos: 871280384 Relay_Log_Space: 19994786573 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: 1594 Last_SQL_Error: Relay log read failure: Could not parse relay log event entry. The possible reasons are: the master's binary log is corrupted (you can check this by running 'mysqlbinlog' on the binary log), the slave's relay log is corrupted (you can check this by running 'mysqlbinlog' on the relay log), a network problem, or a bug in the master's or slave's MySQL code. If you want to check the master's binary log or slave's relay log, you will be able to know their names by issuing 'SHOW SLAVE STATUS' on this slave. 1 row in set (0.00 sec) ERROR: No query specified
原因：
我在master节点上删除了名称为mysql-bin.00007格式的文件，其中包括mysql-bin.000075，因此，slave库找不到该文件，无法同步。
解决办法：