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.

2019-12-19 11:03:24 21717 [ERROR] Error in Log_event::read_log_event(): 'read error', data_len: 7650, event_type: 30
2019-12-19 11:03:24 21717 [ERROR] Error reading relay log event: slave SQL thread aborted because of I/O error
2019-12-19 11:03:24 21717 [ERROR] Slave SQL: 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. Error_code: 1594
2019-12-19 11:03:24 21717 [ERROR] Slave (additional info): Error reading file '/data01/mysql_3323_gdocrimg03/relaylog/relay-bin.000894' (Errcode: 5 - Input/output error) Error_code: 2
2019-12-19 11:03:24 21717 [Warning] Slave: Error reading file '/data01/mysql_3323_gdocrimg03/relaylog/relay-bin.000894' (Errcode: 5 - Input/output error) Error_code: 2
2019-12-19 11:03:24 21717 [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.000301' position 838365877

检查binlog未发现异常，重新change后搞定。