OSA (Optimizer Statistics Advisor)

-- выключение OSA
BEGIN
  dbms_auto_task_admin.disable(
    client_name =>  'auto optimizer stats collection',
    operation   => NULL,
    window_name => NULL
  );
END;
/

-- включение OSA
BEGIN
  dbms_auto_task_admin.enable(
    client_name =>  'auto optimizer stats collection',
    operation   => NULL,
    window_name => NULL
  );
END;
/