anchor.diff:  
   
   -spec handle_cast(term(), #state{}) -> {noreply, #state{}}.
  +handle_cast({prepare_qbuf_dir, ok}, State) ->
  +    {noreply, State#state{status = ready}};
  +handle_cast({prepare_qbuf_dir, {error, Reason}}, State) ->
  +    {noreply, State#state{status = {init_failed, Reason}}};
   handle_cast(tick, State) ->
       do_reap_expired_qbufs(State);
   handle_cast(_Msg, State) ->
  
positive.code:     schedule_tick().
  
  -spec handle_call(term(), pid() | {pid(), term()}, #state{}) -> {reply, term(), #state{}}.
  %% @private
  handle_call({get_or_create_qbuf, SQL, NSubqueries, OrigDDL, Options}, _From, State) ->
      do_get_or_create_qbuf(SQL, NSubqueries, OrigDDL, Options, State);
  
  
negative.code:     %% don't bother recovering any leftover tables
      case riak_kv_ts_util:rm_rf(RootPath) of
          ok ->
              gen_server:cast(?SERVER, {prepare_qbuf_dir, ok});
          {error, Reason1} ->
              lager:warning("Found old data in qbuf dir \"~s\" could not be removed: ~p", [RootPath, Reason1]),
              gen_server:cast(?SERVER, {prepare_qbuf_dir, ok})
              %% eleveldb:open may fail, users beware
      end,
      case filelib:ensure_dir(RootPath) of
          ok ->
              gen_server:cast(?SERVER, {prepare_qbuf_dir, ok});
          {error, Reason2} ->
              lager:warning("Could not create qbuf dir \"~s\": ~p", [RootPath, Reason2]),
              gen_server:cast(?SERVER, {prepare_qbuf_dir, {fail, Reason2}})
      end.
  
  schedule_tick() ->
  