SQL Statements for Controlling Replica Servers 2754 PRIVILEGE_CHECKS_USER Names a user account that supplies a security context for the specified channel.  NULL , which is the default, means no security context is used. PRIVILEGE_CHECKS_USER  is available as of MySQL 8.0.18. The user name and host name for the user account must follow the syntax described in Section 6.2.4, “Specifying Account Names” , and the user must not be an anonymous user (with a blank user name) or the CURRENT_USER . The account must have the  REPLICATION_APPLIER privilege, plus the required privileges to execute the transactions replicated on the channel. For details of the privileges required by the account, see Section 17.3.3, “Replication Privilege Checks” . When you restart the replication channel, the privilege checks are applied from that point on. If you do not specify a channel and no other channels exist, the statement is applied to the default channel. The use of row-based binary logging is strongly recommended when  PRIVILEGE_CHECKS_USER  is set, and you can set REQUIRE_ROW_FORMAT  to enforce this. For example, to start privilege checks on the channel  channel_1  on a running replica, issue the following statements: mysql> STOP REPLICA | SLAVE FOR CHANNEL ’channel_1’; mysql> CHANGE MASTER TO PRIVILEGE_CHECKS_USER = ’ priv_repl ’@’ %.example.com ’, REQUIRE_ROW_FORMAT = 1, FOR CHANNEL ’channel_1’; mysql> START REPLICA | SLAVE FOR CHANNEL ’channel_1’; RELAY_LOG_FILE , RELAY_LOG_POS The relay log file name, and the location in that file, at which the replication SQL thread begins reading from the replica’s relay log the next time the thread starts.  RELAY_LOG_FILE  can use either an absolute or relative path, and uses the same base name as MASTER_LOG_FILE . A  CHANGE MASTER TO  statement using  RELAY_LOG_FILE , RELAY_LOG_POS , or both options can be executed on a running replica when the replication SQL thread is stopped. Relay logs are preserved if at least one of the replication SQL thread and the replication I/O thread is running. If both threads are stopped, all relay log files are deleted unless at least one of  RELAY_LOG_FILE or  RELAY_LOG_POS  is specified. For the Group Replication applier channel ( group_replication_applier ), which only has an SQL thread and no I/O thread, this is the case if the SQL thread is stopped, but with that channel you cannot use the  RELAY_LOG_FILE  and RELAY_LOG_POS  options. REQUIRE_ROW_FORMAT Permits only row-based replication events to be processed by the replication channel. This option prevents the replication applier from taking actions such as creating temporary tables and executing LOAD DATA INFILE  requests, which increases the security of the channel. Group Replication channels are automatically created with REQUIRE_ROW_FORMAT  set, and you cannot change the option for those channels. For more information, see Section 17.3.3, “Replication Privilege Checks” .  REQUIRE_ROW_FORMAT  is available as of MySQL 8.0.19.