XML_DB_EVENTS enables or disables XML DB Events.
Changing this parameter through an ALTER SESSION statement affects only the current session. Only users with the XDBADMIN role are allowed to change this parameter in a session.
Changing this parameter through an ALTER SYSTEM statement will make a systemwide change of this parameter; however, the change is only registered by new sessions started after the change. Currently running sessions need to be restarted to pick up the new change. Users must have the ALTER SYSTEM privilege to make a systemwide change.