diff --git a/apps/emqx_management/src/emqx_mgmt_api_clients.erl b/apps/emqx_management/src/emqx_mgmt_api_clients.erl
index 71e94f841..de1fbabde 100644
--- a/apps/emqx_management/src/emqx_mgmt_api_clients.erl
+++ b/apps/emqx_management/src/emqx_mgmt_api_clients.erl
@@ -313,8 +313,14 @@ format_channel_info({_Key, Info, Stats0}) ->
                              inflight, max_inflight, awaiting_rel,
                              max_awaiting_rel, mqueue_len, mqueue_dropped,
                              max_mqueue, heap_size, reductions, mailbox_len,
-                             recv_cnt, recv_msg, recv_oct, recv_pkt, send_cnt,
-                             send_msg, send_oct, send_pkt], NStats),
+                             recv_cnt,
+                             recv_msg, 'recv_msg.qos0', 'recv_msg.qos1', 'recv_msg.qos2',
+                            'recv_msg.dropped', 'recv_msg.dropped.expired',
+                             recv_oct, recv_pkt, send_cnt,
+                             send_msg, 'send_msg.qos0', 'send_msg.qos1', 'send_msg.qos2',
+                            'send_msg.dropped', 'send_msg.dropped.expired',
+                            'send_msg.dropped.queue_full', 'send_msg.dropped.too_large',
+                             send_oct, send_pkt], NStats),
                  maps:with([clientid, username, mountpoint, is_bridge, zone], ClientInfo),
                  maps:with([clean_start, keepalive, expiry_interval, proto_name,
                             proto_ver, peername, connected_at, disconnected_at], ConnInfo),
@@ -373,7 +379,7 @@ match_fun(Ms, Fuzzy) ->
 
 run_fuzzy_match(_, []) ->
     true;
-run_fuzzy_match(E = {_, #{clientinfo := ClientInfo}, _}, [{Key, like, SubStr}|Fuzzy]) ->
+run_fuzzy_match(E = {_, #{clientinfo := ClientInfo}, _}, [{Key, like, SubStr} | Fuzzy]) ->
     Val = case maps:get(Key, ClientInfo, undefined) of
               undefined -> <<>>;
               V -> V
diff --git a/src/emqx.appup.src b/src/emqx.appup.src
index 8e1016cc4..2e300b85e 100644
--- a/src/emqx.appup.src
+++ b/src/emqx.appup.src
@@ -2,6 +2,7 @@
 {VSN,
   [{"4.4.0",
     [ {load_module,emqx_channel,brutal_purge,soft_purge,[]}
+    , {load_module,emqx_connection,brutal_purge,soft_purge,[]}
     , {load_module,emqx_metrics,brutal_purge,soft_purge,[]}
     , {load_module,emqx_session,brutal_purge,soft_purge,[]}
     , {load_module,emqx_alarm,brutal_purge,soft_purge,[]}
@@ -9,6 +10,7 @@
    {<<".*">>,[]}],
   [{"4.4.0",
     [ {load_module,emqx_channel,brutal_purge,soft_purge,[]}
+    , {load_module,emqx_connection,brutal_purge,soft_purge,[]}
     , {load_module,emqx_metrics,brutal_purge,soft_purge,[]}
     , {load_module,emqx_session,brutal_purge,soft_purge,[]}
     , {load_module,emqx_alarm,brutal_purge,soft_purge,[]}
diff --git a/src/emqx_connection.erl b/src/emqx_connection.erl
index 5eeb323b0..2c2cc472d 100644
--- a/src/emqx_connection.erl
+++ b/src/emqx_connection.erl
@@ -176,7 +176,7 @@ start_link(Transport, Socket, Options) ->
 %%--------------------------------------------------------------------
 
 %% @doc Get infos of the connection/channel.
--spec(info(pid()|state()) -> emqx_types:infos()).
+-spec(info(pid() | state()) -> emqx_types:infos()).
 info(CPid) when is_pid(CPid) ->
     call(CPid, info);
 info(State = #state{channel = Channel}) ->
@@ -205,7 +205,7 @@ info(limiter, #state{limiter = Limiter}) ->
     maybe_apply(fun emqx_limiter:info/1, Limiter).
 
 %% @doc Get stats of the connection/channel.
--spec(stats(pid()|state()) -> emqx_types:stats()).
+-spec(stats(pid() | state()) -> emqx_types:stats()).
 stats(CPid) when is_pid(CPid) ->
     call(CPid, stats);
 stats(#state{transport = Transport,
@@ -389,7 +389,7 @@ cancel_stats_timer(State) -> State.
 
 process_msg([], State) ->
     {ok, State};
-process_msg([Msg|More], State) ->
+process_msg([Msg | More], State) ->
     try
         case handle_msg(Msg, State) of
             ok ->
@@ -483,7 +483,7 @@ handle_msg({Passive, _Sock}, State)
 
 handle_msg(Deliver = {deliver, _Topic, _Msg},
            #state{active_n = ActiveN} = State) ->
-    Delivers = [Deliver|emqx_misc:drain_deliver(ActiveN)],
+    Delivers = [Deliver | emqx_misc:drain_deliver(ActiveN)],
     with_channel(handle_deliver, [Delivers], State);
 
 %% Something sent
@@ -657,7 +657,7 @@ parse_incoming(Data, Packets, State = #state{parse_state = ParseState}) ->
             {Packets, State#state{parse_state = NParseState}};
         {ok, Packet, Rest, NParseState} ->
             NState = State#state{parse_state = NParseState},
-            parse_incoming(Rest, [Packet|Packets], NState)
+            parse_incoming(Rest, [Packet | Packets], NState)
     catch
         error:proxy_protocol_config_disabled:_Stk ->
             ?LOG(error,
diff --git a/src/emqx_session.erl b/src/emqx_session.erl
index 6d4b2af34..9648083d9 100644
--- a/src/emqx_session.erl
+++ b/src/emqx_session.erl
@@ -427,8 +427,8 @@ dequeue(ClientInfo, Cnt, Msgs, Q) ->
         {{value, Msg}, Q1} ->
             case emqx_message:is_expired(Msg) of
                 true ->
-                    ok = emqx_hooks:run('delivery.dropped', [ClientInfo, Msg, expired]),
                     ok = inc_delivery_expired_cnt(),
+                    ok = emqx_hooks:run('delivery.dropped', [ClientInfo, Msg, expired]),
                     dequeue(ClientInfo, Cnt, Msgs, Q1);
                 false -> dequeue(ClientInfo, acc_cnt(Msg, Cnt), [Msg | Msgs], Q1)
             end
@@ -503,11 +503,14 @@ log_dropped(ClientInfo, Msg = #message{qos = QoS}, #session{mqueue = Q}) ->
             ok = emqx_hooks:run('delivery.dropped', [ClientInfo, Msg, qos0_msg]),
             ok = emqx_metrics:inc('delivery.dropped'),
             ok = emqx_metrics:inc('delivery.dropped.qos0_msg'),
+            ok = inc_pd('send_msg.dropped'),
             ?LOG(warning, "Dropped qos0 msg: ~s", [emqx_message:format(Msg)]);
         false ->
             ok = emqx_hooks:run('delivery.dropped', [ClientInfo, Msg, queue_full]),
             ok = emqx_metrics:inc('delivery.dropped'),
             ok = emqx_metrics:inc('delivery.dropped.queue_full'),
+            ok = inc_pd('send_msg.dropped'),
+            ok = inc_pd('send_msg.dropped.queue_full'),
             ?LOG(warning, "Dropped msg due to mqueue is full: ~s",
                  [emqx_message:format(Msg)])
     end.
@@ -568,7 +571,8 @@ await(PacketId, Msg, Session = #session{inflight = Inflight}) ->
 %% Retry Delivery
 %%--------------------------------------------------------------------
 
--spec(retry(emqx_types:clientinfo(), session()) -> {ok, session()} | {ok, replies(), timeout(), session()}).
+-spec(retry(emqx_types:clientinfo(), session()) ->
+    {ok, session()} | {ok, replies(), timeout(), session()}).
 retry(ClientInfo, Session = #session{inflight = Inflight, retry_interval = RetryInterval}) ->
     case emqx_inflight:is_empty(Inflight) of
         true  -> {ok, Session};
@@ -680,13 +684,23 @@ inc_delivery_expired_cnt() ->
     inc_delivery_expired_cnt(1).
 
 inc_delivery_expired_cnt(N) ->
+    ok = inc_pd('send_msg.dropped', N),
+    ok = inc_pd('send_msg.dropped.expired', N),
     ok = emqx_metrics:inc('delivery.dropped', N),
     emqx_metrics:inc('delivery.dropped.expired', N).
 
 inc_await_pubrel_timeout(N) ->
+    ok = inc_pd('recv_msg.dropped', N),
+    ok = inc_pd('recv_msg.dropped.expired', N),
     ok = emqx_metrics:inc('messages.dropped', N),
     emqx_metrics:inc('messages.dropped.await_pubrel_timeout', N).
 
+inc_pd(Key) ->
+    inc_pd(Key, 1).
+inc_pd(Key, Inc) ->
+    _ = emqx_pd:inc_counter(Key, Inc),
+    ok.
+
 %%--------------------------------------------------------------------
 %% Next Packet Id
 %%--------------------------------------------------------------------