anchor.diff:  
   
   %% @doc Handle 'state' event
  +handle_sync_event(state_of_workers, _From, StateName, #state{server_pairs = ServerPairs} = State) ->
  +    Ret = [
  +           [{status, CStatus},
  +            {interval, I},
  +            {num_of_batch_procs, N},
  +            {is_locked, L}
  +           ]
  +           || {CStatus, #compaction_worker_state{
  +                           interval = I,
  +                           num_of_batch_procs = N,
  +                           is_locked = L
  +                          }}
  +                  <-  [sys:get_state(WorkerId)
  +                       || {WorkerId,_} <- ServerPairs]
  +          ],
  +    {reply, {ok, Ret}, StateName, State};
   handle_sync_event(state, _From, StateName, #state{status = Status,
                                                     total_num_of_targets = TotalNumOfTargets,
                                                     reserved_targets     = ReservedTargets,
  
positive.code:          lock/1,
           suspend/0, resume/0,
           state/0,
           finish/2, finish/3,
           increase/0,
           decrease/0
  
negative.code: state() ->
      gen_fsm:sync_send_all_state_event(
        ?MODULE, state, ?DEF_TIMEOUT).
  
  
  %% @doc Retrieve the all compaction statuses from the data-compaction's workers
  -spec(state_of_workers() ->
               term()).
  state_of_workers() ->
      gen_fsm:sync_send_all_state_event(
        ?MODULE, state_of_workers, ?DEF_TIMEOUT).
  
  
  %% @doc Terminate a child
  