diff --git a/apps/emqttd/include/emqttd.hrl b/apps/emqttd/include/emqttd.hrl
index f92ff58eb..0f10daf63 100644
--- a/apps/emqttd/include/emqttd.hrl
+++ b/apps/emqttd/include/emqttd.hrl
@@ -56,7 +56,7 @@
 %%------------------------------------------------------------------------------
 -record(mqtt_subscriber, {
     topic    :: binary(),
-    qos = 0  :: non_neg_integer(),
+    qos = 0  :: 0 | 1 | 2,
     subpid   :: pid()
 }).
 
diff --git a/apps/emqttd/src/emqtt_trie.erl b/apps/emqttd/src/emqtt_trie.erl
index 96d1bdd68..e8e326ab4 100644
--- a/apps/emqttd/src/emqtt_trie.erl
+++ b/apps/emqttd/src/emqtt_trie.erl
@@ -62,7 +62,9 @@
 %%%=============================================================================
 
 %%------------------------------------------------------------------------------
-%% @doc Create trie tables.
+%% @doc
+%% Create trie tables.
+%%
 %% @end
 %%------------------------------------------------------------------------------
 -spec mnesia(create | replicate) -> ok.
@@ -78,7 +80,9 @@ mnesia(create) ->
                 {attributes, record_info(fields, trie_node)}]);
 
 %%------------------------------------------------------------------------------
-%% @doc Replicate trie tables.
+%% @doc
+%% Replicate trie tables.
+%%
 %% @end
 %%------------------------------------------------------------------------------
 mnesia(replicate) ->
@@ -90,7 +94,9 @@ mnesia(replicate) ->
 %%%=============================================================================
 
 %%------------------------------------------------------------------------------
-%% @doc Insert topic to trie tree.
+%% @doc
+%% Insert topic to trie tree.
+%%
 %% @end
 %%------------------------------------------------------------------------------
 insert(Topic) when is_binary(Topic) ->
@@ -107,14 +113,18 @@ insert(Topic) when is_binary(Topic) ->
 	end.
 
 %%------------------------------------------------------------------------------
-%% @doc Find trie nodes that match topic.
+%% @doc
+%% Find trie nodes that match topic.
+%%
 %% @end
 %%------------------------------------------------------------------------------
 find(Topic) when is_binary(Topic) ->
     match_node(root, emqttd_topic:words(Topic), []).
 
 %%------------------------------------------------------------------------------
-%% @doc Delete topic to trie tree.
+%% @doc
+%% Delete topic from trie tree.
+%%
 %% @end
 %%------------------------------------------------------------------------------
 delete(Topic) when is_binary(Topic) ->
@@ -128,7 +138,6 @@ delete(Topic) when is_binary(Topic) ->
 		ignore
 	end.
 
-
 %%%=============================================================================
 %%% Internal functions
 %%%=============================================================================
@@ -136,7 +145,7 @@ delete(Topic) when is_binary(Topic) ->
 %%------------------------------------------------------------------------------
 %% @doc
 %% @private
-%% Add one path to trie tree.
+%% Add path to trie tree.
 %%
 %% @end
 %%------------------------------------------------------------------------------
@@ -159,7 +168,7 @@ add_path({Node, Word, Child}) ->
 %%------------------------------------------------------------------------------
 %% @doc
 %% @private
-%% Match node include word or '+'.
+%% Match node with word or '+'.
 %%
 %% @end
 %%------------------------------------------------------------------------------
@@ -177,7 +186,7 @@ match_node(NodeId, [W|Words], ResAcc) ->
 %%------------------------------------------------------------------------------
 %% @doc
 %% @private
-%% Match '#'.
+%% Match node with '#'.
 %%
 %% @end
 %%------------------------------------------------------------------------------
diff --git a/apps/emqttd/src/emqttd_pubsub.erl b/apps/emqttd/src/emqttd_pubsub.erl
index 3b62d1413..f29438804 100644
--- a/apps/emqttd/src/emqttd_pubsub.erl
+++ b/apps/emqttd/src/emqttd_pubsub.erl
@@ -32,15 +32,12 @@
 
 -include("emqttd_packet.hrl").
 
--include_lib("stdlib/include/qlc.hrl").
-
 -behaviour(gen_server).
 
 -define(SERVER, ?MODULE).
 
 %% API Exports 
-
--export([start_link/0, getstats/0]).
+-export([start_link/0]).
 
 -export([create/1,
          subscribe/1, unsubscribe/1,
@@ -49,7 +46,6 @@
          dispatch/2, match/1]).
 
 %% gen_server Function Exports
-
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
          terminate/2, code_change/3]).
 
@@ -71,25 +67,13 @@ start_link() ->
 
 %%------------------------------------------------------------------------------
 %% @doc
-%% Get stats of PubSub.
-%%
-%% @end
-%%------------------------------------------------------------------------------
--spec getstats() -> [{atom(), non_neg_integer()}].
-getstats() ->
-    [{'topics/count', mnesia:table_info(topic, size)},
-     {'subscribers/count', mnesia:table_info(topic_subscriber, size)},
-     {'subscribers/max', emqttd_broker:getstat('subscribers/max')}].
-
-%%------------------------------------------------------------------------------
-%% @doc
-%% Create static topic.
+%% Create topic.
 %%
 %% @end
 %%------------------------------------------------------------------------------
 -spec create(binary()) -> ok.
 create(Topic) when is_binary(Topic) ->
-    {atomic, ok} = mnesia:transaction(fun add_topic/1, [emqttd_topic:new(Topic)]), ok.
+    {atomic, ok} = mnesia:transaction(fun insert_topic/1, [emqttd_topic:new(Topic)]), ok.
 
 %%------------------------------------------------------------------------------
 %% @doc
@@ -97,28 +81,38 @@ create(Topic) when is_binary(Topic) ->
 %%
 %% @end
 %%------------------------------------------------------------------------------
--spec subscribe({binary(), mqtt_qos()} | list()) -> {ok, list(mqtt_qos())}.
-subscribe({Topic, Qos}) when is_binary(Topic) ->
-    case subscribe([{Topic, Qos}]) of
-        {ok, [GrantedQos]} -> {ok, GrantedQos};
-        {error, Error} -> {error, Error}
-    end;
-subscribe(Topics = [{_Topic, _Qos}|_]) ->
-    subscribe(Topics, self(), []).
+-spec subscribe({Topic, Qos} | list({Topic, Qos})) -> {ok, Qos | list(Qos)} when 
+    Topic   :: binary(),
+    Qos     :: mqtt_qos().
+subscribe(Topics = [{Topic, Qos}|_]) when is_binary(Topic) andalso ?IS_QOS(Qos) ->
+    subscribe2(Topics, []).
 
-subscribe([], _SubPid, Acc) ->
-    {ok, lists:reverse(Acc)};
-subscribe([{Topic, Qos}|Topics], SubPid, Acc) ->
-    TopicObj = emqttd_topic:new(Topic),
-    Subscriber = #topic_subscriber{topic = Topic, qos = Qos, subpid = SubPid},
-    F = fun() -> trie_add(TopicObj), mnesia:write(Subscriber) end,
+-spec subscribe(Topic :: binary(), Qos :: mqtt_qos()) -> {ok, Qos :: mqtt_qos()}.
+subscribe(Topic, Qos) when is_binary(Topic) andalso ?IS_QOS(Qos) ->
+    TopicRecord = emqttd_topic:new(Topic),
+    Subscriber = #mqtt_subscriber{topic = Topic, qos = Qos, subpid = self()},
+    F = fun() ->
+            case insert_topic(TopicRecord) of
+               ok -> insert_subscriber(Subscriber);
+               Error -> Error
+            end
+        end,
     case mnesia:transaction(F) of
-        {atomic, ok} -> 
-            subscribe(Topics, SubPid, [Qos|Acc]);
-        Error -> 
-            {error, Error}
+        {atomic, ok} -> {ok, Qos};
+        Error -> Error
     end.
 
+subscribe2([], QosAcc) ->
+    {ok, lists:reverse(QosAcc)};
+subscribe2([{Topic, Qos}|Topics], Acc) ->
+    case subscribe(Topic, Qos) of
+        {ok, GrantedQos} ->
+            subscribe2(Topics, [GrantedQos|Acc]);
+        Error ->
+            Error
+    end.
+            
+
 %%------------------------------------------------------------------------------
 %% @doc
 %% Unsubscribe Topic or Topics
@@ -283,7 +277,7 @@ code_change(_OldVsn, State, _Extra) ->
 %%		ok
 %%	end.
 %%
-add_topic(Topic = #topic{name = Name, node = Node}) ->
+insert_topic(Topic = #mqtt_topic{name = Name, node = Node}) ->
     case mnesia:wread(topic, Name) of
         [] ->
             trie_add(Name),
diff --git a/apps/emqttd/src/emqttd_topic.erl b/apps/emqttd/src/emqttd_topic.erl
index 6db37dd46..f7584d901 100644
--- a/apps/emqttd/src/emqttd_topic.erl
+++ b/apps/emqttd/src/emqttd_topic.erl
@@ -28,11 +28,13 @@
 
 -author('feng@emqtt.io').
 
+-include("emqttd.hrl").
+
 -import(lists, [reverse/1]).
  
--export([new/1, new/2, wildcard/1, match/2, validate/1, triples/1, words/1]).
+-export([new/1, wildcard/1, match/2, validate/1, triples/1, words/1]).
 
--type type()   :: static | dynamic.
+%-type type()   :: static | dynamic.
 
 -type word()   :: '' | '+' | '#' | binary().
 
@@ -40,7 +42,7 @@
 
 -type triple() :: {root | binary(), word(), binary()}.
 
--export_type([type/0, word/0, triple/0]).
+-export_type([word/0, triple/0]).
 
 -define(MAX_TOPIC_LEN, 65535).
 
@@ -50,40 +52,29 @@
 %%
 %% @end
 %%%-----------------------------------------------------------------------------
--spec new(binary()) -> topic().
+-spec new(binary()) -> mqtt_topic().
 new(Name) when is_binary(Name) ->
-	#topic{name = Name, node = node()}.
+	#mqtt_topic{name = Name, node = node()}.
 
 %%%-----------------------------------------------------------------------------
 %% @doc
-%% New Topic with Type
+%% Is Wildcard Topic?
 %%
 %% @end
 %%%-----------------------------------------------------------------------------
--spec new(type(), binary()) -> topic().
-new(Type, Name) when (Type =:= static orelse Type =:= dynamic) andalso is_binary(Name) ->
-	#topic{name = Name, type = Type, node = node()}.
-
-%%%-----------------------------------------------------------------------------
-%% @doc
-%% Is Wildcard Topic.
-%%
-%% @end
-%%%-----------------------------------------------------------------------------
--spec wildcard(topic() | binary()) -> true | false.
-wildcard(#topic{name = Name}) when is_binary(Name) ->
+-spec wildcard(mqtt_topic() | binary()) -> true | false.
+wildcard(#mqtt_topic{name = Name}) when is_binary(Name) ->
 	wildcard(Name);
 wildcard(Topic) when is_binary(Topic) ->
-	wildcard2(words(Topic)).
-
-wildcard2([]) -> 
+	wildcard(words(Topic));
+wildcard([]) -> 
     false;
-wildcard2(['#'|_]) ->
+wildcard(['#'|_]) ->
     true;
-wildcard2(['+'|_]) ->
+wildcard(['+'|_]) ->
     true;
-wildcard2([_H |T]) ->
-    wildcard2(T).
+wildcard([_H|T]) ->
+    wildcard(T).
 
 %%%-----------------------------------------------------------------------------
 %% @doc
@@ -130,7 +121,7 @@ validate({filter, Topic}) when is_binary(Topic) ->
 	validate2(words(Topic));
 validate({name, Topic}) when is_binary(Topic) ->
 	Words = words(Topic),
-	validate2(Words) and (not include_wildcard(Words)).
+	validate2(Words) and (not wildcard(Words)).
 
 validate2([]) ->
     true;
@@ -155,11 +146,6 @@ validate3(<<C/utf8, _Rest/binary>>) when C == $#; C == $+; C == 0 ->
 validate3(<<_/utf8, Rest/binary>>) ->
     validate3(Rest).
 
-include_wildcard([])        -> false;
-include_wildcard(['#'|_T])  -> true;
-include_wildcard(['+'|_T])  -> true;
-include_wildcard([ _ | T])  -> include_wildcard(T).
-
 %%%-----------------------------------------------------------------------------
 %% @doc
 %% Topic to Triples.
@@ -202,4 +188,3 @@ word(<<"+">>) -> '+';
 word(<<"#">>) -> '#';
 word(Bin)     -> Bin.
 
-