Revert changes to async_nif and re-enable stats. Fixed selective recv.

c_src/async_nif.h

@@ -393,10 +393,8 @@ async_nif_worker_fn(void *arg)
       /* Queue is empty so we wait for more work to arrive. */
       if (q->num_workers > ASYNC_NIF_MIN_WORKERS) {
           enif_mutex_unlock(q->reqs_mutex);
-	  if (tries == 0 && q == we->q) {
+          if (tries == 0 && q == we->q) break; // we've tried all queues, thread exit
-	      tries = async_nif->num_queues;
+          else {
-	      continue;
-	  } else {
               tries--;
               __sync_fetch_and_add(&q->num_workers, -1);
               q = q->next;

src/async_nif.hrl

@@ -21,22 +21,28 @@
 %%
 %% -------------------------------------------------------------------
 
--define(ASYNC_NIF_CALL(Fun, Args),
+-spec async_nif_enqueue(function(), [term()]) -> term() | {error, term()}.
-        begin
+async_nif_enqueue(F, A) ->
-            NIFRef = erlang:make_ref(),
+    R = erlang:make_ref(),
-            case erlang:apply(Fun, [NIFRef|Args]) of
+    case erlang:apply(F, [R|A]) of
         {ok, enqueued} ->
             receive
-                        {NIFRef, {error, shutdown}=Error} ->
+                {R, {error, shutdown}=Error} ->
                     %% Work unit was queued, but not executed.
                     Error;
-                        {NIFRef, {error, _Reason}=Error} ->
+                {R, {error, _Reason}=Error} ->
                     %% Work unit returned an error.
                     Error;
-                        {NIFRef, Reply} ->
+                {R, Reply} ->
                     Reply
             end;
+        {error, eagain} ->
+            %% Work unit was not queued, try again.
+            async_nif_enqueue(F, A);
+        %{error, enomem} ->
+        %{error, shutdown} ->
         Other ->
             Other
-            end
+    end.
-        end).
+
+-define(ASYNC_NIF_CALL(Fun, Args), async_nif_enqueue(Fun, Args)).

src/riak_kv_wterl_backend.erl

@@ -340,26 +340,23 @@ is_empty(#state{connection=Connection, table=Table}) ->
 
 %% @doc Get the status information for this wterl backend
 -spec status(state()) -> [{atom(), term()}].
-status(_) ->
+status(#state{connection=Connection, table=Table}) ->
-    [].
+    case wterl:cursor_open(Connection, Table) of
-
+        {ok, Cursor} ->
-%% status(#state{connection=Connection, table=Table}) ->
+	    TheStats =
-%%     case wterl:cursor_open(Connection, Table) of
+		case fetch_status(Cursor) of
-%%         {ok, Cursor} ->
+		    {ok, Stats} ->
-%% 	    TheStats =
+			Stats;
-%% 		case fetch_status(Cursor) of
+		    {error, {eperm, _}} -> % TODO: review/fix this logic
-%% 		    {ok, Stats} ->
+			{ok, []};
-%% 			Stats;
+		    _ ->
-%% 		    {error, {eperm, _}} -> % TODO: review/fix this logic
+			{ok, []}
-%% 			{ok, []};
+		end,
-%% 		    _ ->
+	    wterl:cursor_close(Cursor),
-%% 			{ok, []}
+	    TheStats;
-%% 		end,
+        {error, Reason2} ->
-%% 	    wterl:cursor_close(Cursor),
+            {error, Reason2}
-%% 	    TheStats;
+    end.
-%%         {error, Reason2} ->
-%%             {error, Reason2}
-%%     end.
 
 %% @doc Register an asynchronous callback
 -spec callback(reference(), any(), state()) -> {ok, state()}.
@@ -546,15 +543,15 @@ from_index_key(LKey) ->
 
 %% @private
 %% Return all status from wterl statistics cursor
-%% fetch_status(Cursor) ->
+fetch_status(Cursor) ->
-%%    {ok, fetch_status(Cursor, wterl:cursor_next_value(Cursor), [])}.
+   {ok, fetch_status(Cursor, wterl:cursor_next_value(Cursor), [])}.
-%% fetch_status(_Cursor, {error, _}, Acc) ->
+fetch_status(_Cursor, {error, _}, Acc) ->
-%%     lists:reverse(Acc);
+    lists:reverse(Acc);
-%% fetch_status(_Cursor, not_found, Acc) ->
+fetch_status(_Cursor, not_found, Acc) ->
-%%     lists:reverse(Acc);
+    lists:reverse(Acc);
-%% fetch_status(Cursor, {ok, Stat}, Acc) ->
+fetch_status(Cursor, {ok, Stat}, Acc) ->
-%%     [What,Val|_] = [binary_to_list(B) || B <- binary:split(Stat, [<<0>>], [global])],
+    [What,Val|_] = [binary_to_list(B) || B <- binary:split(Stat, [<<0>>], [global])],
-%%     fetch_status(Cursor, wterl:cursor_next_value(Cursor), [{What,Val}|Acc]).
+    fetch_status(Cursor, wterl:cursor_next_value(Cursor), [{What,Val}|Acc]).
 
 size_cache(RequestedSize) ->
     Size =