Server System Variables for which to track assignments. By default, notification is enabled for  time_zone ,  autocommit , character_set_client ,  character_set_results , and  character_set_connection . (The latter three variables are those affected by  SET NAMES .) The special value  *  causes the server to track assignments to all session variables. If given, this value must be specified by itself without specific system variable names. To disable notification of session variable assignments, set  session_track_system_variables  to the empty string. If session system variable tracking is enabled, notification occurs for all assignments to tracked session variables, even if the new values are the same as the old. For more information about session state tracking, see Section 5.1.18, “Server Tracking of Client Session State Changes” . • session_track_transaction_info • OFF : Disable transaction state tracking. This is the default. • STATE : Enable transaction state tracking without characteristics tracking. State tracking enables the client to determine whether a transaction is in progress and whether it could be moved to a different session without being rolled back. • CHARACTERISTICS : Enable transaction state tracking, including characteristics tracking. Characteristics tracking enables the client to determine how to restart a transaction in another session so that it has the same characteristics as in the original session. The following characteristics are relevant for this purpose: Controls whether the server tracks the state and characteristics of transactions within the current session and notifies the client to make this information available. These  session_track_transaction_info values are permitted: For a client to safely relocate a transaction to another session, it must track not only transaction state but also transaction characteristics. In addition, the client must track the  transaction_isolation ISOLATION LEVEL READ ONLY READ WRITE WITH CONSISTENT SNAPSHOT 876 Command-Line Format --session-track-transaction- info=value System Variable session_track_transaction_info Scope Global, Session Dynamic Yes SET_VAR  Hint Applies No Type Enumeration Default Value OFF Valid Values OFF STATE CHARACTERISTICS