Replication and Binary Logging Options and Variables also get performance benefits from enabling this system variable, because they use the same locking mechanisms as the replicas. Limit callbacks to improve performance for semisynchronous replication. This setting and replication_optimize_for_static_plugin_config  help as the number of replicas increases, because contention for locks can slow down performance. This system variable can be enabled before or after installing the semisynchronous replication plugin, and can be enabled while replication is running. Semisynchronous replication source servers can also get performance benefits from enabling this system variable, because they use the same locking mechanisms as the replicas. The host name or IP address of the replica to be reported to the source during replica registration. This value appears in the output of  SHOW REPLICAS | SHOW SLAVE HOSTS  on the source server. Leave the value unset if you do not want the replica to register itself with the source. It is not sufficient for the source to simply read the IP address of the replica server from the TCP/IP socket after the replica connects. Due to NAT and other routing issues, that IP may not be valid for connecting to the replica from the source or other hosts. • report_password • replication_sender_observe_commit_only • report_host Command-Line Format --replication-sender-observe-commit- only[={OFF|ON}] Introduced 8.0.23 System Variable replication_sender_observe_commit_only Scope Global Dynamic Yes SET_VAR  Hint Applies No Type Boolean Default Value OFF Command-Line Format --report-host=host_name System Variable report_host Scope Global Dynamic No SET_VAR  Hint Applies No Type String Command-Line Format --report-password=name System Variable report_password Scope Global 3524 Note