SQL Statements for Controlling Replica Servers REQUIRE_TABLE_PRIMARY_KEY_CHECK Enables a replica to select its own policy for primary key checks. When the option is set to  ON  for a replication channel, the replica always uses the value  ON  for the  sql_require_primary_key system variable in replication operations, requiring a primary key. When the option is set to  OFF , the replica always uses the value  OFF for the  sql_require_primary_key  system variable in replication operations, so that a primary key is never required, even if the source required one. When the  REQUIRE_TABLE_PRIMARY_KEY_CHECK option is set to  STREAM , which is the default, the replica uses whatever value is replicated from the source for each transaction. REQUIRE_TABLE_PRIMARY_KEY_CHECK  is available as of MySQL 8.0.20. For multisource replication, setting REQUIRE_TABLE_PRIMARY_KEY_CHECK  to  ON  or  OFF  enables a replica to normalize behavior across the replication channels for different sources, and keep a consistent setting for the sql_require_primary_key  system variable. Using  ON  safeguards against the accidental loss of primary keys when multiple sources update the same set of tables. Using  OFF  allows sources that can manipulate primary keys to work alongside sources that cannot. When  PRIVILEGE_CHECKS_USER  is set, setting REQUIRE_TABLE_PRIMARY_KEY_CHECK  to  ON  or  OFF  means that the user account does not need session administration level privileges to set restricted session variables, which are required to change the value of  sql_require_primary_key  to match the source’s setting for each transaction. For more information, see Section 17.3.3, “Replication Privilege Checks” . SOURCE_CONNECTION_AUTO_FAILOVER Activates the asynchronous connection failover mechanism for a replication channel if one or more alternative replication source servers are available (so when there are multiple MySQL servers or groups of servers that share the replicated data).  SOURCE_CONNECTION_AUTO_FAILOVER  is available as of MySQL 8.0.22. The asynchronous connection failover mechanism takes over after the reconnection attempts controlled by  MASTER_CONNECT_RETRY  and  MASTER_RETRY_COUNT  are exhausted. It reconnects the replica to an alternative source chosen from a specified source list, which you manage using the asynchronous_connection_failover_add_source  and asynchronous_connection_failover_delete_source functions. To add and remove managed groups of servers, use the asynchronous_connection_failover_add_managed  and asynchronous_connection_failover_delete_managed functions instead. For more information, see Section 17.4.9, “Switching Sources with Asynchronous Connection Failover” . Important 1. You can only set SOURCE_CONNECTION_AUTO_FAILOVER = 1  when GTID auto-positioning is in use ( MASTER_AUTO_POSITION = 1 ). 2755