anchor.diff:  find_by_limit(Rows, Acc) when Rows == length(Acc) ->
       {ok, Acc};
   find_by_limit(Rows, []) ->
  -    Table =  ?TBL_CLUSTER_INFO,
  +    Table = ?TBL_CLUSTER_INFO,
       case catch mnesia:ets(fun ets:first/1, [Table]) of
           {'EXIT', Cause} ->
               {error, Cause};
  
positive.code:                    num_of_rack_replicas = Level2,
                     max_mdc_targets = ?DEF_MAX_MDC_TARGETS
                    }.
  
negative.code: find_by_limit(Rows,_ClusterId, Acc) when Rows == length(Acc) ->
      {ok, Acc};
  find_by_limit(Rows, ClusterId, Acc) ->
      Table = ?TBL_CLUSTER_INFO,
      case catch mnesia:ets(fun ets:next/2, [Table, ClusterId]) of
          {'EXIT', Cause} ->
              {error, Cause};
  