Group Replication System Variables • group_replication_enforce_update_everywhere_checks • group_replication_gtid_assignment_block_size • group_replication_view_change_uuid • default_table_encryption • lower_case_table_names • transaction_write_set_extraction  (deprecated from MySQL 8.0.26) • group_replication_transaction_size_limit • group_replication_message_cache_size • group_replication_compression_threshold • group_replication_communication_max_message_size • group_replication_auto_increment_increment • group_replication_advertise_recovery_endpoints • group_replication_autorejoin_tries • group_replication_consistency • group_replication_exit_state_action • group_replication_flow_control_applier_threshold • group_replication_flow_control_certifier_threshold • group_replication_flow_control_hold_percent • group_replication_flow_control_max_commit_quota • group_replication_flow_control_member_quota_percent • group_replication_flow_control_min_quota • group_replication_flow_control_min_recovery_quota • group_replication_flow_control_mode 3794 Most system variables for Group Replication are described as dynamic, and their values can be changed while the server is running. However, in most cases, the change only takes effect after you stop and restart Group Replication on the group member using a  STOP GROUP_REPLICATION  statement followed by a START GROUP_REPLICATION  statement. Changes to the following system variables take effect without stopping and restarting Group Replication: Most system variables for Group Replication can have different values on different group members. For the following system variables, it is advisable to set the same value on all members of a group in order to avoid unnecessary rollback of transactions, failure of message delivery, or failure of message recovery: From MySQL 8.0.16, you can use the  group_replication_switch_to_single_primary_mode() and  group_replication_switch_to_multi_primary_mode()  functions to change the values of  group_replication_single_primary_mode  and group_replication_enforce_update_everywhere_checks  while the group is still running. For more information, see Section 18.5.1.2, “Changing a Group’s Mode” .