diff --git a/src/emqx_connection.erl b/src/emqx_connection.erl
index e1d4011fc..2f596068c 100644
--- a/src/emqx_connection.erl
+++ b/src/emqx_connection.erl
@@ -16,15 +16,12 @@
 
 -behaviour(gen_server).
 
--define(LOG_HEADER, "[TCP]").
-
 -include("emqx.hrl").
 -include("emqx_mqtt.hrl").
 -include("logger.hrl").
 
 -export([start_link/3]).
--export([info/1, attrs/1]).
--export([stats/1]).
+-export([info/1, attrs/1, stats/1]).
 -export([kick/1]).
 -export([session/1]).
 
@@ -46,11 +43,12 @@
           stats_timer,
           incoming,
           rate_limit,
-          publish_limit,
+          pub_limit,
           limit_timer,
           idle_timeout
          }).
 
+-define(LOG_HEADER, "[TCP]").
 -define(DEFAULT_ACTIVE_N, 100).
 -define(SOCK_STATS, [recv_oct, recv_cnt, send_oct, send_cnt, send_pend]).
 
@@ -65,22 +63,22 @@ start_link(Transport, Socket, Options) ->
 info(CPid) when is_pid(CPid) ->
     call(CPid, info);
 
-info(#state{transport     = Transport,
-            socket        = Socket,
-            peername      = Peername,
-            sockname      = Sockname,
-            conn_state    = ConnState,
-            active_n      = ActiveN,
-            rate_limit    = RateLimit,
-            publish_limit = PubLimit,
-            proto_state   = ProtoState}) ->
+info(#state{transport   = Transport,
+            socket      = Socket,
+            peername    = Peername,
+            sockname    = Sockname,
+            conn_state  = ConnState,
+            active_n    = ActiveN,
+            rate_limit  = RateLimit,
+            pub_limit   = PubLimit,
+            proto_state = ProtoState}) ->
     ConnInfo = [{socktype, Transport:type(Socket)},
                 {peername, Peername},
                 {sockname, Sockname},
                 {conn_state, ConnState},
                 {active_n, ActiveN},
                 {rate_limit, esockd_rate_limit:info(RateLimit)},
-                {publish_limit, esockd_rate_limit:info(PubLimit)}],
+                {pub_limit, esockd_rate_limit:info(PubLimit)}],
     ProtoInfo = emqx_protocol:info(ProtoState),
     lists:usort(lists:append(ConnInfo, ProtoInfo)).
 
@@ -139,22 +137,21 @@ init([Transport, RawSocket, Options]) ->
                                               peercert => Peercert,
                                               sendfun  => SendFun}, Options),
             ParserState = emqx_protocol:parser(ProtoState),
-            State = run_socket(#state{transport     = Transport,
-                                      socket        = Socket,
-                                      peername      = Peername,
-                                      conn_state    = running,
-                                      active_n      = ActiveN,
-                                      rate_limit    = RateLimit,
-                                      publish_limit = PubLimit,
-                                      proto_state   = ProtoState,
-                                      parser_state  = ParserState,
-                                      enable_stats  = EnableStats,
-                                      idle_timeout  = IdleTimout
+            State = run_socket(#state{transport    = Transport,
+                                      socket       = Socket,
+                                      peername     = Peername,
+                                      conn_state   = running,
+                                      active_n     = ActiveN,
+                                      rate_limit   = RateLimit,
+                                      pub_limit    = PubLimit,
+                                      proto_state  = ProtoState,
+                                      parser_state = ParserState,
+                                      enable_stats = EnableStats,
+                                      idle_timeout = IdleTimout
                                      }),
             GcPolicy = emqx_zone:get_env(Zone, force_gc_policy, false),
             ok = emqx_gc:init(GcPolicy),
             ok = emqx_misc:init_proc_mng_policy(Zone),
-
             emqx_logger:set_metadata_peername(esockd_net:format(Peername)),
             gen_server:enter_loop(?MODULE, [{hibernate_after, IdleTimout}],
                                   State, self(), IdleTimout);
@@ -213,6 +210,7 @@ handle_info({deliver, PubOrAck}, State = #state{proto_state = ProtoState}) ->
         {error, Reason} ->
             shutdown(Reason, State)
     end;
+
 handle_info({timeout, Timer, emit_stats},
             State = #state{stats_timer = Timer,
                            proto_state = ProtoState
@@ -231,6 +229,7 @@ handle_info({timeout, Timer, emit_stats},
             ?LOG(warning, "shutdown due to ~p", [Reason]),
             shutdown(Reason, NewState)
     end;
+
 handle_info(timeout, State) ->
     shutdown(idle_timeout, State);
 
@@ -331,9 +330,9 @@ handle_packet(<<>>, State) ->
 handle_packet(Data, State = #state{proto_state  = ProtoState,
                                    parser_state = ParserState,
                                    idle_timeout = IdleTimeout}) ->
-    case catch emqx_frame:parse(Data, ParserState) of
-        {more, NewParserState} ->
-            {noreply, State#state{parser_state = NewParserState}, IdleTimeout};
+    try emqx_frame:parse(Data, ParserState) of
+        {more, ParserState1} ->
+            {noreply, State#state{parser_state = ParserState1}, IdleTimeout};
         {ok, Packet = ?PACKET(Type), Rest} ->
             emqx_metrics:received(Packet),
             case emqx_protocol:received(Packet, ProtoState) of
@@ -348,11 +347,12 @@ handle_packet(Data, State = #state{proto_state  = ProtoState,
                 {stop, Error, ProtoState1} ->
                     stop(Error, State#state{proto_state = ProtoState1})
             end;
-        {error, Error} ->
-            ?LOG(error, "Framing error - ~p", [Error]),
-            shutdown(Error, State);
-        {'EXIT', Reason} ->
-            ?LOG(error, "Parse failed for ~p~nError data:~p", [Reason, Data]),
+        {error, Reason} ->
+            ?LOG(error, "Parse frame error - ~p", [Reason]),
+            shutdown(Reason, State)
+    catch
+        _:Error ->
+            ?LOG(error, "Parse failed for ~p~nError data:~p", [Error, Data]),
             shutdown(parse_error, State)
     end.
 
@@ -370,9 +370,9 @@ inc_publish_cnt(_Type, State) ->
 %% Ensure rate limit
 %%------------------------------------------------------------------------------
 
-ensure_rate_limit(State = #state{rate_limit = Rl, publish_limit = Pl,
+ensure_rate_limit(State = #state{rate_limit = Rl, pub_limit = Pl,
                                  incoming = #{packets := Packets, bytes := Bytes}}) ->
-    ensure_rate_limit([{Pl, #state.publish_limit, Packets},
+    ensure_rate_limit([{Pl, #state.pub_limit, Packets},
                        {Rl, #state.rate_limit, Bytes}], State).
 
 ensure_rate_limit([], State) ->
@@ -421,3 +421,4 @@ maybe_gc(#state{}, {publish, _PacketId, #message{payload = Payload}}) ->
     ok = emqx_gc:inc(1, Oct);
 maybe_gc(_, _) ->
     ok.
+