Add debug loggin

src/hanoi_level.erl

@@ -55,6 +55,21 @@
           opts = [], owner, work_done=0
           }).
 
+
+-ifdef(DEBUG).
+-define(log(Fmt,Args), debug_log(State,Fmt,Args)).
+debug_log(State,Fmt,Args) ->
+    Files = [if State#state.c == undefined -> $ ; true -> $C end,
+             if State#state.b == undefined -> $ ; true -> $B end,
+             if State#state.a == undefined -> $ ; true -> $A end ],
+    io:format("~s~p[~s]: " ++ Fmt, [if State#state.level < 10 -> "0"; true -> "" end,
+                                    State#state.level,
+                                    Files] ++ Args),
+    ok.
+-else.
+-define(log(Fmt,Args),ok).
+-endif.
+
 %%%%% PUBLIC OPERATIONS
 
 open(Dir,Level,Next,Opts,Owner) when Level>0 ->
@@ -218,11 +233,27 @@ main_loop(State = #state{ next=Next }) ->
                     ToFileName = filename("C",State),
                     SetPos = #state.c
             end,
-            ok = file:rename(FileName, ToFileName),
-            {ok, BT} = hanoi_reader:open(ToFileName, random),
 
-            reply(From, ok),
+            ?log("inject ~s~n", [ToFileName]),
+
+            case file:rename(FileName, ToFileName) of
+                ok -> ok;
+                E  -> ?log("rename failed ~p -> ~p :: ~p~n", [FileName, ToFileName, E]),
+                      error(E)
+            end,
+
+            plain_rpc:send_reply(From, ok),
+
+            case hanoi_reader:open(ToFileName, random) of
+                {ok, BT} ->
+                    if SetPos == #state.b ->
                             check_begin_merge_then_loop(setelement(SetPos, State, BT));
+                       true ->
+                            main_loop(setelement(SetPos, State, BT))
+                    end;
+                E2  -> ?log("open failed ~p :: ~p~n", [ToFileName, E2]),
+                      error(E2)
+            end;
 
 
         ?CALL(From, unmerged_count) ->
@@ -252,6 +283,8 @@ main_loop(State = #state{ next=Next }) ->
             WorkToDoHere = min(WorkLeftHere, HowMuch),
             DelegateWork = max(0,HowMuch - WorkToDoHere),
 
+            ?log("step:~p, do:~p, left:~p ~n", [HowMuch, WorkToDoHere, WorkLeftHere]),
+
             %% delegate the step request to the next level
             if Next =:= undefined; DelegateWork == 0 ->
                     DelegateRef = undefined;
@@ -464,6 +497,9 @@ main_loop(State = #state{ next=Next }) ->
         %% We need to push the output of merging to the next level
         %%
         ?CAST(_,{merge_done, _Count, OutFileName}) ->
+
+            ?log("merge_done, out:~w, next:~p~n", [_Count,Next]),
+
             State1 =
                 if Next =:= undefined ->
                         {ok, PID} = ?MODULE:open(State#state.dir, State#state.level + 1, undefined,
@@ -516,6 +552,8 @@ main_loop(State = #state{ next=Next }) ->
             %% Probably from a merger_pid - which we may have forgotten in the meantime.
             main_loop(State);
         {'EXIT', Pid, Reason} when Pid == State#state.merge_pid ->
+
+            ?log("*** merge_died: ~p~n", [Reason]),
             restart_merge_then_loop(State#state{merge_pid=undefined}, Reason);
         {'EXIT', PID, _} when [PID] == tl(State#state.folding);
                               hd(State#state.folding) == PID ->
@@ -523,6 +561,7 @@ main_loop(State = #state{ next=Next }) ->
         {'EXIT', PID, Reason} ->
             error_logger:info_msg("got unexpected exit ~p from ~p~n", [Reason, PID])
 
+
     end.
 
 reply_step_ok(State) ->
@@ -577,15 +616,18 @@ begin_merge(State) ->
     XFileName = filename("X",State),
     Owner = self(),
 
+    ?log("starting merge~n", []),
+
     file:delete(XFileName),
 
     MergePID = proc_lib:spawn_link(fun() ->
          try
+                       ?log("merge begun", []),
+
                        {ok, OutCount} = hanoi_merger:merge(AFileName, BFileName, XFileName,
                                                            ?BTREE_SIZE(State#state.level + 1),
                                                            State#state.next =:= undefined,
                                                            State#state.opts ),
-%                       error_logger:info_msg("merge done ~p,~p -> ~p~n", [AFileName, BFileName, XFileName]),
 
                        Owner ! ?CAST(self(),{merge_done, OutCount, XFileName})
          catch