refactor: Move deliver and persist out of server context

The session routing is keeping track of the subscriptions of persistent sessions.

Makefile

@@ -15,6 +15,8 @@ REL_PROFILES := emqx emqx-edge
 PKG_PROFILES := emqx-pkg emqx-edge-pkg
 PROFILES := $(REL_PROFILES) $(PKG_PROFILES) default
 
+CT_NODE_NAME ?= 'test@127.0.0.1'
+
 export REBAR_GIT_CLONE_OPTIONS += --depth=1
 
 .PHONY: default
@@ -44,7 +46,7 @@ proper: $(REBAR)
 
 .PHONY: ct
 ct: $(REBAR)
-	@ENABLE_COVER_COMPILE=1 $(REBAR) ct --name 'test@127.0.0.1' -c -v
+	@ENABLE_COVER_COMPILE=1 $(REBAR) ct --name $(CT_NODE_NAME) -c -v
 
 APPS=$(shell $(CURDIR)/scripts/find-apps.sh)
 
@@ -52,7 +54,7 @@ APPS=$(shell $(CURDIR)/scripts/find-apps.sh)
 .PHONY: $(APPS:%=%-ct)
 define gen-app-ct-target
 $1-ct:
-	$(REBAR) ct --name 'test@127.0.0.1' -v --suite $(shell $(CURDIR)/scripts/find-suites.sh $1)
+	$(REBAR) ct --name $(CT_NODE_NAME) -v --suite $(shell $(CURDIR)/scripts/find-suites.sh $1)
 endef
 $(foreach app,$(APPS),$(eval $(call gen-app-ct-target,$(app))))
 
@@ -64,6 +66,14 @@ $1-prop:
 endef
 $(foreach app,$(APPS),$(eval $(call gen-app-prop-target,$(app))))
 
+.PHONY: ct-suite
+ct-suite: $(REBAR)
+ifneq ($(TESTCASE),)
+	$(REBAR) ct -v --readable=false --name $(CT_NODE_NAME) --suite $(SUITE)  --case $(TESTCASE)
+else
+	$(REBAR) ct -v --readable=false --name $(CT_NODE_NAME) --suite $(SUITE)
+endif
+
 .PHONY: cover
 cover: $(REBAR)
 	@ENABLE_COVER_COMPILE=1 $(REBAR) cover

apps/emqx/include/emqx.hrl

@@ -26,6 +26,7 @@
 -define(COMMON_SHARD, emqx_common_shard).
 -define(SHARED_SUB_SHARD, emqx_shared_sub_shard).
 -define(MOD_DELAYED_SHARD, emqx_delayed_shard).
+-define(PERSISTENT_SESSION_SHARD, emqx_persistent_session_shard).
 
 %%--------------------------------------------------------------------
 %% Banner
@@ -89,7 +90,7 @@
 
 -record(route, {
           topic :: binary(),
-          dest  :: node() | {binary(), node()}
+          dest  :: node() | {binary(), node()} | binary()
          }).
 
 %%--------------------------------------------------------------------

apps/emqx/src/emqx_app.erl

@@ -38,6 +38,7 @@
                      , ?SHARED_SUB_SHARD
                      , ?RULE_ENGINE_SHARD
                      , ?MOD_DELAYED_SHARD
+                     , ?PERSISTENT_SESSION_SHARD
                      ]).
 
 

apps/emqx/src/emqx_broker.erl

@@ -205,6 +205,7 @@ publish(Msg) when is_record(Msg, message) ->
             ?LOG(notice, "Stop publishing: ~s", [emqx_message:format(Msg)]),
             [];
         Msg1 = #message{topic = Topic} ->
+            emqx_session_router:persist(Msg1),
             route(aggre(emqx_router:match_routes(Topic)), delivery(Msg1))
     end.
 

apps/emqx/src/emqx_channel.erl

@@ -183,7 +183,11 @@ set_conn_state(ConnState, Channel) ->
 get_session(#channel{session = Session}) ->
     Session.
 
-set_session(Session, Channel) ->
+set_session(Session, Channel = #channel{clientinfo = ClientInfo, conninfo = ConnInfo}) ->
+    %% Assume that this is also an updated session. Allow side effect.
+    ClientID = maps:get(clientid, ClientInfo, undefined),
+    ExpiryInterval = maps:get(expiry_interval, ConnInfo, 0),
+    emqx_session:db_put(ClientID, ExpiryInterval, Session),
     Channel#channel{session = Session}.
 
 %% TODO: Add more stats.
@@ -367,10 +371,10 @@ handle_in(?PUBACK_PACKET(PacketId, _ReasonCode, Properties), Channel
     case emqx_session:puback(PacketId, Session) of
         {ok, Msg, NSession} ->
             ok = after_message_acked(ClientInfo, Msg, Properties),
-            {ok, Channel#channel{session = NSession}};
+            {ok, set_session(NSession, Channel)};
         {ok, Msg, Publishes, NSession} ->
             ok = after_message_acked(ClientInfo, Msg, Properties),
-            handle_out(publish, Publishes, Channel#channel{session = NSession});
+            handle_out(publish, Publishes, set_session(NSession, Channel));
         {error, ?RC_PACKET_IDENTIFIER_IN_USE} ->
             ?LOG(warning, "The PUBACK PacketId ~w is inuse.", [PacketId]),
             ok = emqx_metrics:inc('packets.puback.inuse'),
@@ -386,7 +390,7 @@ handle_in(?PUBREC_PACKET(PacketId, _ReasonCode, Properties), Channel
     case emqx_session:pubrec(PacketId, Session) of
         {ok, Msg, NSession} ->
             ok = after_message_acked(ClientInfo, Msg, Properties),
-            NChannel = Channel#channel{session = NSession},
+            NChannel = set_session(NSession, Channel),
             handle_out(pubrel, {PacketId, ?RC_SUCCESS}, NChannel);
         {error, RC = ?RC_PACKET_IDENTIFIER_IN_USE} ->
             ?LOG(warning, "The PUBREC PacketId ~w is inuse.", [PacketId]),
@@ -401,7 +405,7 @@ handle_in(?PUBREC_PACKET(PacketId, _ReasonCode, Properties), Channel
 handle_in(?PUBREL_PACKET(PacketId, _ReasonCode), Channel = #channel{session = Session}) ->
     case emqx_session:pubrel(PacketId, Session) of
         {ok, NSession} ->
-            NChannel = Channel#channel{session = NSession},
+            NChannel = set_session(NSession, Channel),
             handle_out(pubcomp, {PacketId, ?RC_SUCCESS}, NChannel);
         {error, RC = ?RC_PACKET_IDENTIFIER_NOT_FOUND} ->
             ?LOG(warning, "The PUBREL PacketId ~w is not found.", [PacketId]),
@@ -412,9 +416,9 @@ handle_in(?PUBREL_PACKET(PacketId, _ReasonCode), Channel = #channel{session = Se
 handle_in(?PUBCOMP_PACKET(PacketId, _ReasonCode), Channel = #channel{session = Session}) ->
     case emqx_session:pubcomp(PacketId, Session) of
         {ok, NSession} ->
-            {ok, Channel#channel{session = NSession}};
+            {ok, set_session(NSession, Channel)};
         {ok, Publishes, NSession} ->
-            handle_out(publish, Publishes, Channel#channel{session = NSession});
+            handle_out(publish, Publishes, set_session(NSession, Channel));
         {error, ?RC_PACKET_IDENTIFIER_IN_USE} ->
             ok = emqx_metrics:inc('packets.pubcomp.inuse'),
             {ok, Channel};
@@ -614,7 +618,8 @@ do_publish(PacketId, Msg = #message{qos = ?QOS_2},
     case emqx_session:publish(PacketId, Msg, Session) of
         {ok, PubRes, NSession} ->
             RC = puback_reason_code(PubRes),
-            NChannel1 = ensure_timer(await_timer, Channel#channel{session = NSession}),
+            NChannel0 = set_session(NSession, Channel),
+            NChannel1 = ensure_timer(await_timer, NChannel0),
             NChannel2 = ensure_quota(PubRes, NChannel1),
             handle_out(pubrec, {PacketId, RC}, NChannel2);
         {error, RC = ?RC_PACKET_IDENTIFIER_IN_USE} ->
@@ -683,7 +688,7 @@ do_subscribe(TopicFilter, SubOpts = #{qos := QoS}, Channel =
     NSubOpts = enrich_subopts(maps:merge(?DEFAULT_SUBOPTS, SubOpts), Channel),
     case emqx_session:subscribe(ClientInfo, NTopicFilter, NSubOpts, Session) of
         {ok, NSession} ->
-            {QoS, Channel#channel{session = NSession}};
+            {QoS, set_session(NSession, Channel)};
         {error, RC} ->
             ?LOG(warning, "Cannot subscribe ~s due to ~s.",
                  [TopicFilter, emqx_reason_codes:text(RC)]),
@@ -711,7 +716,7 @@ do_unsubscribe(TopicFilter, SubOpts, Channel =
     TopicFilter1 = emqx_mountpoint:mount(MountPoint, TopicFilter),
     case emqx_session:unsubscribe(ClientInfo, TopicFilter1, SubOpts, Session) of
         {ok, NSession} ->
-            {?RC_SUCCESS, Channel#channel{session = NSession}};
+            {?RC_SUCCESS, set_session(NSession, Channel)};
         {error, RC} -> {RC, Channel}
     end.
 %%--------------------------------------------------------------------
@@ -736,7 +741,9 @@ process_disconnect(ReasonCode, Properties, Channel) ->
 
 maybe_update_expiry_interval(#{'Session-Expiry-Interval' := Interval},
                              Channel = #channel{conninfo = ConnInfo}) ->
-    Channel#channel{conninfo = ConnInfo#{expiry_interval => timer:seconds(Interval)}};
+    NChannel = Channel#channel{conninfo = ConnInfo#{expiry_interval => timer:seconds(Interval)}},
+    %% We need to update the expiry interval on the session as well
+    set_session(NChannel#channel.session, NChannel);
 maybe_update_expiry_interval(_Properties, Channel) -> Channel.
 
 %%--------------------------------------------------------------------
@@ -748,8 +755,14 @@ maybe_update_expiry_interval(_Properties, Channel) -> Channel.
 handle_deliver(Delivers, Channel = #channel{conn_state = disconnected,
                                             session    = Session,
                                             clientinfo = #{clientid := ClientId}}) ->
-    NSession = emqx_session:enqueue(ignore_local(maybe_nack(Delivers), ClientId, Session), Session),
-    {ok, Channel#channel{session = NSession}};
+    Delivers1 = maybe_nack(Delivers),
+    Delivers2 = ignore_local(Delivers1, ClientId, Session),
+    NSession = emqx_session:enqueue(Delivers2, Session),
+    NChannel = set_session(NSession, Channel),
+    %% We consider queued/dropped messages as delivered since they are now in the session state.
+    MsgIds = [emqx_message:id(Msg) || {deliver, _, Msg} <- Delivers],
+    emqx_session_router:delivered(ClientId, MsgIds),
+    {ok, NChannel};
 
 handle_deliver(Delivers, Channel = #channel{takeover = true,
                                             pendings = Pendings,
@@ -759,13 +772,22 @@ handle_deliver(Delivers, Channel = #channel{takeover = true,
     {ok, Channel#channel{pendings = NPendings}};
 
 handle_deliver(Delivers, Channel = #channel{session = Session,
-                                            clientinfo = #{clientid := ClientId}}) ->
+                                            clientinfo = #{clientid := ClientId},
+                                            conninfo = #{expiry_interval := ExpiryInterval}
+                                           }) ->
     case emqx_session:deliver(ignore_local(Delivers, ClientId, Session), Session) of
         {ok, Publishes, NSession} ->
-            NChannel = Channel#channel{session = NSession},
+            NChannel = set_session(NSession, Channel),
+            case ExpiryInterval > 0 of
+                true ->
+                    MsgIds = [emqx_message:id(Msg) || {deliver, _, Msg} <- Delivers],
+                    emqx_session_router:delivered(ClientId, MsgIds);
+                false ->
+                    ignore
+            end,
             handle_out(publish, Publishes, ensure_timer(retry_timer, NChannel));
         {ok, NSession} ->
-            {ok, Channel#channel{session = NSession}}
+            {ok, set_session(NSession, Channel)}
     end.
 
 ignore_local(Delivers, Subscriber, Session) ->
@@ -881,13 +903,13 @@ return_connack(AckPacket, Channel) ->
     case maybe_resume_session(Channel) of
         ignore -> {ok, Replies, Channel};
         {ok, Publishes, NSession} ->
-            NChannel = Channel#channel{session  = NSession,
-                                       resuming = false,
+            NChannel0 = Channel#channel{resuming = false,
                                        pendings = []
                                       },
-            {Packets, NChannel1} = do_deliver(Publishes, NChannel),
+            NChannel1 = set_session(NSession, NChannel0),
+            {Packets, NChannel2} = do_deliver(Publishes, NChannel1),
             Outgoing = [{outgoing, Packets} || length(Packets) > 0],
-            {ok, Replies ++ Outgoing, NChannel1}
+            {ok, Replies ++ Outgoing, NChannel2}
     end.
 
 %%--------------------------------------------------------------------
@@ -1047,9 +1069,9 @@ handle_timeout(_TRef, retry_delivery,
                Channel = #channel{session = Session}) ->
     case emqx_session:retry(Session) of
         {ok, NSession} ->
-            {ok, clean_timer(retry_timer, Channel#channel{session = NSession})};
+            {ok, clean_timer(retry_timer, set_session(NSession, Channel))};
         {ok, Publishes, Timeout, NSession} ->
-            NChannel = Channel#channel{session = NSession},
+            NChannel = set_session(NSession, Channel),
             handle_out(publish, Publishes, reset_timer(retry_timer, Timeout, NChannel))
     end;
 
@@ -1060,9 +1082,9 @@ handle_timeout(_TRef, expire_awaiting_rel,
                Channel = #channel{session = Session}) ->
     case emqx_session:expire(awaiting_rel, Session) of
         {ok, NSession} ->
-            {ok, clean_timer(await_timer, Channel#channel{session = NSession})};
+            {ok, clean_timer(await_timer, set_session(NSession, Channel))};
         {ok, Timeout, NSession} ->
-            {ok, reset_timer(await_timer, Timeout, Channel#channel{session = NSession})}
+            {ok, reset_timer(await_timer, Timeout, set_session(NSession, Channel))}
     end;
 
 handle_timeout(_TRef, expire_session, Channel) ->
@@ -1598,8 +1620,12 @@ maybe_resume_session(#channel{resuming = false}) ->
     ignore;
 maybe_resume_session(#channel{session  = Session,
                               resuming = true,
-                              pendings = Pendings}) ->
+                              pendings = Pendings,
+                              clientinfo = #{clientid := ClientId}}) ->
     {ok, Publishes, Session1} = emqx_session:replay(Session),
+    %% We consider queued/dropped messages as delivered since they are now in the session state.
+    MsgIds = [emqx_message:id(Msg) || {deliver, _, Msg} <- Pendings],
+    emqx_session_router:delivered(ClientId, MsgIds),
     case emqx_session:deliver(Pendings, Session1) of
         {ok, Session2} ->
             {ok, Publishes, Session2};

apps/emqx/src/emqx_cm.erl

@@ -211,21 +211,34 @@ set_chan_stats(ClientId, ChanPid, Stats) ->
                 pendings => list()}}
        | {error, Reason :: term()}).
 open_session(true, ClientInfo = #{clientid := ClientId}, ConnInfo) ->
+    EI = maps:get(expiry_interval, ConnInfo, 0),
     Self = self(),
     CleanStart = fun(_) ->
                      ok = discard_session(ClientId),
                      Session = create_session(ClientInfo, ConnInfo),
+                     emqx_session:db_put(ClientId, EI, Session),
                      register_channel(ClientId, Self, ConnInfo),
                      {ok, #{session => Session, present => false}}
                  end,
     emqx_cm_locker:trans(ClientId, CleanStart);
 
 open_session(false, ClientInfo = #{clientid := ClientId}, ConnInfo) ->
+    EI = maps:get(expiry_interval, ConnInfo, 0),
     Self = self(),
     ResumeStart = fun(_) ->
                       case takeover_session(ClientId) of
+                          {ok, Session} ->
+                              ok = emqx_session:resume(ClientInfo, Session),
+                              emqx_session:db_put(ClientId, EI, Session),
+                              Pendings = [{deliver, emqx_message:topic(Msg), Msg}
+                                          || Msg <- emqx_session_router:pending(ClientId)],
+                              register_channel(ClientId, Self, ConnInfo),
+                              {ok, #{session  => Session,
+                                     present  => true,
+                                     pendings => Pendings}};
                           {ok, ConnMod, ChanPid, Session} ->
                               ok = emqx_session:resume(ClientInfo, Session),
+                              emqx_session:db_put(ClientId, EI, Session),
                               Pendings = ConnMod:call(ChanPid, {takeover, 'end'}, ?T_TAKEOVER),
                               register_channel(ClientId, Self, ConnInfo),
                               {ok, #{session  => Session,
@@ -233,6 +246,7 @@ open_session(false, ClientInfo = #{clientid := ClientId}, ConnInfo) ->
                                      pendings => Pendings}};
                           {error, not_found} ->
                               Session = create_session(ClientInfo, ConnInfo),
+                              emqx_session:db_put(ClientId, EI, Session),
                               register_channel(ClientId, Self, ConnInfo),
                               {ok, #{session => Session, present => false}}
                       end
@@ -271,7 +285,11 @@ get_mqtt_conf(Zone, Key) ->
        | {ok, atom(), pid(), emqx_session:session()}).
 takeover_session(ClientId) ->
     case lookup_channels(ClientId) of
+        [] ->
+            case emqx_session:db_get(ClientId) of
                 [] -> {error, not_found};
+                [Session] -> {ok, Session}
+            end;
         [ChanPid] ->
             takeover_session(ClientId, ChanPid);
         ChanPids ->
@@ -286,7 +304,10 @@ takeover_session(ClientId) ->
 takeover_session(ClientId, ChanPid) when node(ChanPid) == node() ->
     case get_chann_conn_mod(ClientId, ChanPid) of
         undefined ->
-            {error, not_found};
+            case emqx_session:db_get(ClientId) of
+                [] -> {error, not_found};
+                [Session] -> {ok, Session}
+            end;
         ConnMod when is_atom(ConnMod) ->
             Session = ConnMod:call(ChanPid, {takeover, 'begin'}, ?T_TAKEOVER),
             {ok, ConnMod, ChanPid, Session}

apps/emqx/src/emqx_router.erl

@@ -119,8 +119,10 @@ do_add_route(Topic, Dest) when is_binary(Topic) ->
             ok = emqx_router_helper:monitor(Dest),
             case emqx_topic:wildcard(Topic) of
                 true  ->
-                    maybe_trans(fun insert_trie_route/1, [Route]);
-                false -> insert_direct_route(Route)
+                    Fun = fun emqx_router_utils:insert_trie_route/2,
+                    emqx_router_utils:maybe_trans(Fun, [?ROUTE_TAB, Route], ?ROUTE_SHARD);
+                false ->
+                    emqx_router_utils:insert_direct_route(?ROUTE_TAB, Route)
             end
     end.
 
@@ -165,8 +167,10 @@ do_delete_route(Topic, Dest) ->
     Route = #route{topic = Topic, dest = Dest},
     case emqx_topic:wildcard(Topic) of
         true  ->
-            maybe_trans(fun delete_trie_route/1, [Route]);
-        false -> delete_direct_route(Route)
+            Fun = fun emqx_router_utils:delete_trie_route/2,
+            emqx_router_utils:maybe_trans(Fun, [?ROUTE_TAB, Route], ?ROUTE_SHARD);
+        false ->
+            emqx_router_utils:delete_direct_route(?ROUTE_TAB, Route)
     end.
 
 -spec(topics() -> list(emqx_topic:topic())).
@@ -219,100 +223,3 @@ terminate(_Reason, #{pool := Pool, id := Id}) ->
 
 code_change(_OldVsn, State, _Extra) ->
     {ok, State}.
-
-%%--------------------------------------------------------------------
-%% Internal functions
-%%--------------------------------------------------------------------
-
-insert_direct_route(Route) ->
-    ekka_mnesia:dirty_write(?ROUTE_TAB, Route).
-
-insert_trie_route(Route = #route{topic = Topic}) ->
-    case mnesia:wread({?ROUTE_TAB, Topic}) of
-        [] -> emqx_trie:insert(Topic);
-        _  -> ok
-    end,
-    mnesia:write(?ROUTE_TAB, Route, sticky_write).
-
-delete_direct_route(Route) ->
-    ekka_mnesia:dirty_delete_object(?ROUTE_TAB, Route).
-
-delete_trie_route(Route = #route{topic = Topic}) ->
-    case mnesia:wread({?ROUTE_TAB, Topic}) of
-        [Route] -> %% Remove route and trie
-                  ok = mnesia:delete_object(?ROUTE_TAB, Route, sticky_write),
-                   emqx_trie:delete(Topic);
-        [_|_]   -> %% Remove route only
-                   mnesia:delete_object(?ROUTE_TAB, Route, sticky_write);
-        []      -> ok
-    end.
-
-%% @private
--spec(maybe_trans(function(), list(any())) -> ok | {error, term()}).
-maybe_trans(Fun, Args) ->
-    case emqx_config:get([broker, perf, route_lock_type]) of
-        key ->
-            trans(Fun, Args);
-        global ->
-            %% Assert:
-            mnesia = ekka_rlog:backend(), %% TODO: do something smarter than just crash
-            lock_router(),
-            try mnesia:sync_dirty(Fun, Args)
-            after
-                unlock_router()
-            end;
-        tab ->
-            trans(fun() ->
-                          emqx_trie:lock_tables(),
-                          apply(Fun, Args)
-                  end, [])
-    end.
-
-%% The created fun only terminates with explicit exception
--dialyzer({nowarn_function, [trans/2]}).
-
--spec(trans(function(), list(any())) -> ok | {error, term()}).
-trans(Fun, Args) ->
-    {WPid, RefMon} =
-        spawn_monitor(
-            %% NOTE: this is under the assumption that crashes in Fun
-            %% are caught by mnesia:transaction/2.
-            %% Future changes should keep in mind that this process
-            %% always exit with database write result.
-            fun() ->
-                    Res = case ekka_mnesia:transaction(?ROUTE_SHARD, Fun, Args) of
-                              {atomic, Ok} -> Ok;
-                              {aborted, Reason} -> {error, Reason}
-                          end,
-                    exit({shutdown, Res})
-            end),
-    %% Receive a 'shutdown' exit to pass result from the short-lived process.
-    %% so the receive below can be receive-mark optimized by the compiler.
-    %%
-    %% If the result is sent as a regular message, we'll have to
-    %% either demonitor (with flush which is essentially a 'receive' since
-    %% the process is no longer alive after the result has been received),
-    %% or use a plain 'receive' to drain the normal 'DOWN' message.
-    %% However the compiler does not optimize this second 'receive'.
-    receive
-        {'DOWN', RefMon, process, WPid, Info} ->
-            case Info of
-                {shutdown, Result} -> Result;
-                _ -> {error, {trans_crash, Info}}
-            end
-    end.
-
-lock_router() ->
-    %% if Retry is not 0, global:set_lock could sleep a random time up to 8s.
-    %% Considering we have a limited number of brokers, it is safe to use sleep 1 ms.
-    case global:set_lock({?MODULE, self()}, [node() | nodes()], 0) of
-        false ->
-            %% Force to sleep 1ms instead.
-            timer:sleep(1),
-            lock_router();
-        true ->
-            ok
-    end.
-
-unlock_router() ->
-    global:del_lock({?MODULE, self()}).

apps/emqx/src/emqx_router_sup.erl

@@ -34,7 +34,13 @@ init([]) ->
                type     => worker,
                modules  => [emqx_router_helper]},
     %% Router pool
-    RouterPool = emqx_pool_sup:spec([router_pool, hash,
+    RouterPool = emqx_pool_sup:spec(router_pool,
+                                    [router_pool, hash,
                                      {emqx_router, start_link, []}]),
-    {ok, {{one_for_all, 0, 1}, [Helper, RouterPool]}}.
+
+    %% TODO: Should this be optional?
+    SessionRouterPool = emqx_pool_sup:spec(session_router_pool,
+                                           [session_router_pool, hash,
+                                            {emqx_session_router, start_link, []}]),
+    {ok, {{one_for_all, 0, 1}, [Helper, RouterPool, SessionRouterPool]}}.
 

apps/emqx/src/emqx_router_utils.erl

@@ -0,0 +1,126 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2017-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_router_utils).
+
+-include("emqx.hrl").
+
+-export([ delete_direct_route/2
+        , delete_trie_route/2
+        , insert_direct_route/2
+        , insert_trie_route/2
+        , maybe_trans/3
+        ]).
+
+insert_direct_route(Tab, Route) ->
+    ekka_mnesia:dirty_write(Tab, Route).
+
+insert_trie_route(RouteTab, Route = #route{topic = Topic}) ->
+    case mnesia:wread({RouteTab, Topic}) of
+        [] when RouteTab =:= emqx_route         -> emqx_trie:insert(Topic);
+        [] when RouteTab =:= emqx_session_route -> emqx_trie:insert_session(Topic);
+        _  -> ok
+    end,
+    mnesia:write(RouteTab, Route, sticky_write).
+
+delete_direct_route(RouteTab, Route) ->
+    ekka_mnesia:dirty_delete_object(RouteTab, Route).
+
+delete_trie_route(RouteTab, Route = #route{topic = Topic}) ->
+    case mnesia:wread({RouteTab, Topic}) of
+        [R] when R =:= Route ->
+            %% Remove route and trie
+            ok = mnesia:delete_object(RouteTab, Route, sticky_write),
+            case RouteTab of
+                emqx_route         -> emqx_trie:delete(Topic);
+                emqx_session_route -> emqx_trie:delete_session(Topic)
+            end;
+        [_|_]   ->
+            %% Remove route only
+            mnesia:delete_object(RouteTab, Route, sticky_write);
+        [] ->
+            ok
+    end.
+
+%% @private
+-spec(maybe_trans(function(), list(any()), Shard :: atom()) -> ok | {error, term()}).
+maybe_trans(Fun, Args, Shard) ->
+    case emqx_config:get([broker, perf, route_lock_type]) of
+        key ->
+            trans(Fun, Args, Shard);
+        global ->
+            %% Assert:
+            mnesia = ekka_rlog:backend(), %% TODO: do something smarter than just crash
+            lock_router(Shard),
+            try mnesia:sync_dirty(Fun, Args)
+            after
+                unlock_router(Shard)
+            end;
+        tab ->
+            trans(fun() ->
+                          emqx_trie:lock_tables(),
+                          apply(Fun, Args)
+                  end, [], Shard)
+    end.
+
+%% The created fun only terminates with explicit exception
+-dialyzer({nowarn_function, [trans/3]}).
+
+-spec(trans(function(), list(any()), atom()) -> ok | {error, term()}).
+trans(Fun, Args, Shard) ->
+    {WPid, RefMon} =
+        spawn_monitor(
+            %% NOTE: this is under the assumption that crashes in Fun
+            %% are caught by mnesia:transaction/2.
+            %% Future changes should keep in mind that this process
+            %% always exit with database write result.
+            fun() ->
+                    Res = case ekka_mnesia:transaction(Shard, Fun, Args) of
+                              {atomic, Ok} -> Ok;
+                              {aborted, Reason} -> {error, Reason}
+                          end,
+                    exit({shutdown, Res})
+            end),
+    %% Receive a 'shutdown' exit to pass result from the short-lived process.
+    %% so the receive below can be receive-mark optimized by the compiler.
+    %%
+    %% If the result is sent as a regular message, we'll have to
+    %% either demonitor (with flush which is essentially a 'receive' since
+    %% the process is no longer alive after the result has been received),
+    %% or use a plain 'receive' to drain the normal 'DOWN' message.
+    %% However the compiler does not optimize this second 'receive'.
+    receive
+        {'DOWN', RefMon, process, WPid, Info} ->
+            case Info of
+                {shutdown, Result} -> Result;
+                _ -> {error, {trans_crash, Info}}
+            end
+    end.
+
+lock_router(Shard) ->
+    %% if Retry is not 0, global:set_lock could sleep a random time up to 8s.
+    %% Considering we have a limited number of brokers, it is safe to use sleep 1 ms.
+    case global:set_lock({{?MODULE, Shard}, self()}, [node() | nodes()], 0) of
+        false ->
+            %% Force to sleep 1ms instead.
+            timer:sleep(1),
+            lock_router(Shard);
+        true ->
+            ok
+    end.
+
+unlock_router(Shard) ->
+    global:del_lock({{?MODULE, Shard}, self()}).

apps/emqx/src/emqx_session.erl

@@ -54,6 +54,15 @@
 -compile(nowarn_export_all).
 -endif.
 
+%% DB API
+-export([ mnesia/1
+        , db_get/1
+        , db_put/3
+        ]).
+
+-boot_mnesia({mnesia, [boot]}).
+-copy_mnesia({mnesia, [copy]}).
+
 -export([init/1]).
 
 -export([ info/1
@@ -159,6 +168,27 @@
                     , mqueue => emqx_mqueue:options()
                     }.
 
+%%--------------------------------------------------------------------
+%% Mnesia bootstrap
+%%--------------------------------------------------------------------
+
+-define(SESSION_STORE, emqx_session_store).
+-record(session_store, { id               :: binary()
+                       , expiry_interval  :: non_neg_integer()
+                       , ts               :: non_neg_integer()
+                       , session          :: #session{}}).
+
+mnesia(boot) ->
+    ok = ekka_mnesia:create_table(?SESSION_STORE, [
+                {type, set},
+                {ram_copies, [node()]},
+                {record_name, session_store},
+                {attributes, record_info(fields, session_store)},
+                {storage_properties, [{ets, [{read_concurrency, true}]}]}]);
+
+mnesia(copy) ->
+    ok = ekka_mnesia:copy_table(?SESSION_STORE, ram_copies).
+
 %%--------------------------------------------------------------------
 %% Init a Session
 %%--------------------------------------------------------------------
@@ -184,6 +214,51 @@ init(Opts) ->
        created_at        = erlang:system_time(millisecond)
       }.
 
+%%--------------------------------------------------------------------
+%% DB API
+%%--------------------------------------------------------------------
+
+db_put(undefined,_ExpiryInterval, #session{}) ->
+    ok;
+db_put(SessionID, ExpiryInterval, #session{} = Session) when is_binary(SessionID),
+                                                             is_integer(ExpiryInterval) ->
+    SS = #session_store{ id              = SessionID
+                       , expiry_interval = ExpiryInterval
+                       , ts              = erlang:system_time(millisecond)
+                       , session         = Session},
+    case use_db_session(SS) of
+        false -> clean_up_session(SessionID, Session);
+        true  ->
+            %% TODO: Should check for changes in the subscriptions.
+            maps:foreach(fun(Topic, _) ->
+                                 emqx_session_router:do_add_route(Topic, SessionID)
+                         end, Session#session.subscriptions),
+            ekka_mnesia:dirty_write(?SESSION_STORE, SS)
+    end.
+
+db_get(SessionID) when is_binary(SessionID) ->
+    case mnesia:dirty_read(?SESSION_STORE, SessionID) of
+        [] -> [];
+        [#session_store{session = S} = SS] ->
+            case use_db_session(SS) of
+                true  -> [S];
+                false -> []
+            end
+    end.
+
+%% @private [MQTT-3.1.2-23]
+use_db_session(#session_store{expiry_interval = 0}) ->
+    false;
+use_db_session(#session_store{expiry_interval = 16#FFFFFFFF}) ->
+    true;
+use_db_session(#session_store{expiry_interval = E, ts = TS}) ->
+    E*1000 + TS > erlang:system_time(millisecond).
+
+clean_up_session(SessionID, Session) ->
+    Fun = fun(Topic, _) -> emqx_session_router:do_delete_route(Topic, SessionID) end,
+    maps:foreach(Fun, Session#session.subscriptions),
+    ekka_mnesia:dirty_delete(?SESSION_STORE, SessionID).
+
 %%--------------------------------------------------------------------
 %% Info, Stats
 %%--------------------------------------------------------------------
@@ -272,6 +347,8 @@ unsubscribe(ClientInfo, TopicFilter, UnSubOpts, Session = #session{subscriptions
     case maps:find(TopicFilter, Subs) of
         {ok, SubOpts} ->
             ok = emqx_broker:unsubscribe(TopicFilter),
+            ClientID = maps:get(clientid, ClientInfo, undefined),
+            emqx_session_router:do_delete_route(ClientID, TopicFilter),
             ok = emqx_hooks:run('session.unsubscribed', [ClientInfo, TopicFilter, maps:merge(SubOpts, UnSubOpts)]),
             {ok, Session#session{subscriptions = maps:remove(TopicFilter, Subs)}};
         error ->
@@ -637,7 +714,8 @@ terminate(ClientInfo, discarded, Session) ->
     run_hook('session.discarded', [ClientInfo, info(Session)]);
 terminate(ClientInfo, takeovered, Session) ->
     run_hook('session.takeovered', [ClientInfo, info(Session)]);
-terminate(ClientInfo, Reason, Session) ->
+terminate(#{clientid := ClientId} = ClientInfo, Reason, Session) ->
+    clean_up_session(ClientId, Session),
     run_hook('session.terminated', [ClientInfo, Reason, info(Session)]).
 
 -compile({inline, [run_hook/2]}).

apps/emqx/src/emqx_session_router.erl

@@ -0,0 +1,289 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2017-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_session_router).
+
+-behaviour(gen_server).
+
+-include("emqx.hrl").
+-include("logger.hrl").
+-include("types.hrl").
+-include_lib("ekka/include/ekka.hrl").
+
+-logger_header("[Router]").
+
+%% Mnesia bootstrap
+-export([mnesia/1]).
+
+-boot_mnesia({mnesia, [boot]}).
+-copy_mnesia({mnesia, [copy]}).
+
+-export([start_link/2]).
+
+%% Route APIs
+-export([ do_add_route/2
+        , do_delete_route/2
+        , match_routes/1
+        ]).
+
+-export([ persist/1
+        , delivered/2
+        , pending/1
+        ]).
+
+-export([print_routes/1]).
+
+%% gen_server callbacks
+-export([ init/1
+        , handle_call/3
+        , handle_cast/2
+        , handle_info/2
+        , terminate/2
+        , code_change/3
+        ]).
+
+-type(group() :: binary()).
+
+-type(dest() :: node() | {group(), node()}).
+
+-define(ROUTE_TAB, emqx_session_route).
+-define(SESS_MSG_TAB, emqx_session_msg).
+-define(MSG_TAB, emqx_persistent_msg).
+
+%% NOTE: It is important that ?DELIVERED > ?UNDELIVERED because of traversal order
+-define(DELIVERED, 1).
+-define(UNDELIVERED, 0).
+-type pending_tag() :: ?DELIVERED | ?UNDELIVERED.
+-record(session_msg, {key      :: {binary(), emqx_guid:guid(), pending_tag()},
+                      val = [] :: []}).
+
+-rlog_shard({?PERSISTENT_SESSION_SHARD, ?ROUTE_TAB}).
+-rlog_shard({?PERSISTENT_SESSION_SHARD, ?SESS_MSG_TAB}).
+-rlog_shard({?PERSISTENT_SESSION_SHARD, ?MSG_TAB}).
+
+%%--------------------------------------------------------------------
+%% Mnesia bootstrap
+%%--------------------------------------------------------------------
+
+mnesia(boot) ->
+    ok = ekka_mnesia:create_table(?ROUTE_TAB, [
+                {type, bag},
+                {ram_copies, [node()]},
+                {record_name, route},
+                {attributes, record_info(fields, route)},
+                {storage_properties, [{ets, [{read_concurrency, true},
+                                             {write_concurrency, true}]}]}]),
+    ok = ekka_mnesia:create_table(?SESS_MSG_TAB, [
+                {type, ordered_set},
+                {ram_copies, [node()]},
+                {record_name, session_msg},
+                {attributes, record_info(fields, session_msg)},
+                {storage_properties, [{ets, [{read_concurrency, true},
+                                             {write_concurrency, true}]}]}]),
+    %% TODO: This should be external
+    ok = ekka_mnesia:create_table(?MSG_TAB, [
+                {type, set},
+                {ram_copies, [node()]},
+                {record_name, message},
+                {attributes, record_info(fields, message)},
+                {storage_properties, [{ets, [{read_concurrency, true},
+                                             {write_concurrency, true}]}]}]);
+mnesia(copy) ->
+    ok = ekka_mnesia:copy_table(?ROUTE_TAB, ram_copies),
+    ok = ekka_mnesia:copy_table(?SESS_MSG_TAB, ram_copies),
+    %% TODO: This should be external
+    ok = ekka_mnesia:copy_table(?MSG_TAB, ram_copies).
+
+%%--------------------------------------------------------------------
+%% Start a router
+%%--------------------------------------------------------------------
+
+-spec(start_link(atom(), pos_integer()) -> startlink_ret()).
+start_link(Pool, Id) ->
+    gen_server:start_link({local, emqx_misc:proc_name(?MODULE, Id)},
+                          ?MODULE, [Pool, Id], [{hibernate_after, 1000}]).
+
+%%--------------------------------------------------------------------
+%% Route APIs
+%%--------------------------------------------------------------------
+
+-spec(do_add_route(emqx_topic:topic(), dest()) -> ok | {error, term()}).
+do_add_route(Topic, SessionID) when is_binary(Topic) ->
+    Route = #route{topic = Topic, dest = SessionID},
+    case lists:member(Route, lookup_routes(Topic)) of
+        true  -> ok;
+        false ->
+            case emqx_topic:wildcard(Topic) of
+                true  ->
+                    Fun = fun emqx_router_utils:insert_trie_route/2,
+                    emqx_router_utils:maybe_trans(Fun, [?ROUTE_TAB, Route],
+                                                  ?PERSISTENT_SESSION_SHARD);
+                false ->
+                    emqx_router_utils:insert_direct_route(?ROUTE_TAB, Route)
+            end
+    end.
+
+%% @doc Match routes
+-spec(match_routes(emqx_topic:topic()) -> [emqx_types:route()]).
+match_routes(Topic) when is_binary(Topic) ->
+    case match_trie(Topic) of
+        [] -> lookup_routes(Topic);
+        Matched ->
+            lists:append([lookup_routes(To) || To <- [Topic | Matched]])
+    end.
+
+%% Optimize: routing table will be replicated to all router nodes.
+match_trie(Topic) ->
+    case emqx_trie:empty_session() of
+        true -> [];
+        false -> emqx_trie:match_session(Topic)
+    end.
+
+-spec(do_delete_route(emqx_topic:topic(), dest()) -> ok | {error, term()}).
+do_delete_route(Topic, SessionID) ->
+    Route = #route{topic = Topic, dest = SessionID},
+    case emqx_topic:wildcard(Topic) of
+        true  ->
+            Fun = fun emqx_router_utils:delete_trie_route/2,
+            emqx_router_utils:maybe_trans(Fun, [?ROUTE_TAB, Route], ?PERSISTENT_SESSION_SHARD);
+        false ->
+            emqx_router_utils:delete_direct_route(?ROUTE_TAB, Route)
+    end.
+
+%% @doc Print routes to a topic
+-spec(print_routes(emqx_topic:topic()) -> ok).
+print_routes(Topic) ->
+    lists:foreach(fun(#route{topic = To, dest = SessionID}) ->
+                      io:format("~s -> ~s~n", [To, SessionID])
+                  end, match_routes(Topic)).
+
+%%--------------------------------------------------------------------
+%% Message APIs
+%%--------------------------------------------------------------------
+
+persist(Msg) ->
+    case emqx_message:get_flag(dup, Msg) orelse emqx_message:is_sys(Msg) of
+        true  -> ok;
+        false ->
+            case match_routes(emqx_message:topic(Msg)) of
+                [] -> ok;
+                Routes ->
+                    %% TODO: This should store in external backend
+                    ekka_mnesia:dirty_write(?MSG_TAB, Msg),
+                    MsgId = emqx_message:id(Msg),
+                    Fun = fun(#route{dest = SessionID}) ->
+                                  Key = {SessionID, MsgId, ?UNDELIVERED},
+                                  ekka_mnesia:dirty_write(?SESS_MSG_TAB, #session_msg{ key = Key })
+                          end,
+                    lists:foreach(Fun, Routes)
+            end
+    end.
+
+delivered(SessionID, MsgIDs) ->
+    Fun = fun(MsgID) ->
+                  Key = {SessionID, MsgID, ?DELIVERED},
+                  ekka_mnesia:dirty_write(?SESS_MSG_TAB, #session_msg{ key = Key })
+          end,
+    lists:foreach(Fun, MsgIDs),
+
+pending(SessionID) ->
+    call(pick(SessionID), {pending, SessionID}).
+
+call(Router, Msg) ->
+    gen_server:call(Router, Msg, infinity).
+
+cast(Router, Msg) ->
+    gen_server:cast(Router, Msg).
+
+pick(#route{dest = SessionID}) ->
+    gproc_pool:pick_worker(session_router_pool, SessionID);
+pick(SessionID) when is_binary(SessionID) ->
+    gproc_pool:pick_worker(session_router_pool, SessionID).
+
+%%--------------------------------------------------------------------
+%% gen_server callbacks
+%%--------------------------------------------------------------------
+
+init([Pool, Id]) ->
+    true = gproc_pool:connect_worker(Pool, {Pool, Id}),
+    {ok, #{pool => Pool, id => Id}}.
+
+handle_call({pending, SessionID}, _From, State) ->
+    {reply, pending_messages(SessionID), State};
+handle_call(Req, _From, State) ->
+    ?LOG(error, "Unexpected call: ~p", [Req]),
+    {reply, ignored, State}.
+
+handle_cast({delivered, SessionID, MsgIDs}, State) ->
+    Fun = fun(MsgID) ->
+                  Key = {SessionID, MsgID, ?DELIVERED},
+                  ekka_mnesia:dirty_write(?SESS_MSG_TAB, #session_msg{ key = Key })
+          end,
+    lists:foreach(Fun, MsgIDs),
+    {noreply, State};
+handle_cast(Msg, State) ->
+    ?LOG(error, "Unexpected cast: ~p", [Msg]),
+    {noreply, State}.
+
+handle_info(Info, State) ->
+    ?LOG(error, "Unexpected info: ~p", [Info]),
+    {noreply, State}.
+
+terminate(_Reason, #{pool := Pool, id := Id}) ->
+    gproc_pool:disconnect_worker(Pool, {Pool, Id}).
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+%%--------------------------------------------------------------------
+%% Internal functions
+%%--------------------------------------------------------------------
+
+lookup_routes(Topic) ->
+    ets:lookup(?ROUTE_TAB, Topic).
+
+pending_messages(SessionID) ->
+    %% TODO: The reading of messages should be from external DB
+    Fun = fun() -> [hd(mnesia:read(?MSG_TAB, MsgId))
+                    || MsgId <- pending_messages(SessionID, <<>>, ?DELIVERED, [])]
+          end,
+    {atomic, Msgs} = ekka_mnesia:ro_transaction(?PERSISTENT_SESSION_SHARD, Fun),
+    Msgs.
+
+%% The keys are ordered by
+%%     {sessionID(), emqx_guid:guid(), ?DELIVERED | ?UNDELIVERED}
+%%  where
+%%     emqx_guid:guid() is ordered in ts() and by node()
+%%     ?UNDELIVERED < ?DELIVERED
+%%
+%% We traverse the table until we reach another session.
+%% TODO: Garbage collect the delivered messages.
+pending_messages(SessionID, PrevMsgId, PrevTag, Acc) ->
+    case mnesia:dirty_next(?SESS_MSG_TAB, {SessionID, PrevMsgId, PrevTag}) of
+        {S, MsgId, Tag} = Key when S =:= SessionID, MsgId =:= PrevMsgId ->
+            Tag =:= ?UNDELIVERED andalso error({assert_fail}, Key),
+            pending_messages(SessionID, MsgId, Tag, Acc);
+        {S, MsgId, Tag} when S =:= SessionID ->
+            case PrevTag of
+                ?DELIVERED   -> pending_messages(SessionID, MsgId, Tag, Acc);
+                ?UNDELIVERED -> pending_messages(SessionID, MsgId, Tag, [PrevMsgId|Acc])
+            end;
+        _ -> %% Next sessionID or '$end_of_table'
+            case PrevTag of
+                ?DELIVERED   -> lists:reverse(Acc);
+                ?UNDELIVERED -> lists:reverse([PrevMsgId|Acc])
+            end
+    end.

apps/emqx/src/emqx_trie.erl

@@ -26,12 +26,17 @@
 
 %% Trie APIs
 -export([ insert/1
+        , insert_session/1
         , match/1
+        , match_session/1
         , delete/1
+        , delete_session/1
         ]).
 
 -export([ empty/0
+        , empty_session/0
         , lock_tables/0
+        , lock_session_tables/0
         ]).
 
 -export([is_compact/0, set_compact/1]).
@@ -42,6 +47,7 @@
 -endif.
 
 -define(TRIE, emqx_trie).
+-define(SESSION_TRIE, emqx_session_trie).
 -define(PREFIX(Prefix), {Prefix, 0}).
 -define(TOPIC(Topic), {Topic, 1}).
 
@@ -51,6 +57,7 @@
         }).
 
 -rlog_shard({?ROUTE_SHARD, ?TRIE}).
+-rlog_shard({?PERSISTENT_SESSION_SHARD, ?SESSION_TRIE}).
 
 %%--------------------------------------------------------------------
 %% Mnesia bootstrap
@@ -64,6 +71,12 @@ mnesia(boot) ->
                          {write_concurrency, true}
                         ]}],
     ok = ekka_mnesia:create_table(?TRIE, [
+                {ram_copies, [node()]},
+                {record_name, ?TRIE},
+                {attributes, record_info(fields, ?TRIE)},
+                {type, ordered_set},
+                {storage_properties, StoreProps}]),
+    ok = ekka_mnesia:create_table(?SESSION_TRIE, [
                 {ram_copies, [node()]},
                 {record_name, ?TRIE},
                 {attributes, record_info(fields, ?TRIE)},
@@ -71,6 +84,7 @@ mnesia(boot) ->
                 {storage_properties, StoreProps}]);
 mnesia(copy) ->
     %% Copy topics table
+    ok = ekka_mnesia:copy_table(?SESSION_TRIE, ram_copies),
     ok = ekka_mnesia:copy_table(?TRIE, ram_copies).
 
 %%--------------------------------------------------------------------
@@ -80,24 +94,46 @@ mnesia(copy) ->
 %% @doc Insert a topic filter into the trie.
 -spec(insert(emqx_topic:topic()) -> ok).
 insert(Topic) when is_binary(Topic) ->
+    insert(Topic, ?TRIE).
+
+-spec(insert_session(emqx_topic:topic()) -> ok).
+insert_session(Topic) when is_binary(Topic) ->
+    insert(Topic, ?SESSION_TRIE).
+
+insert(Topic, Trie) when is_binary(Topic) ->
     {TopicKey, PrefixKeys} = make_keys(Topic),
-    case mnesia:wread({?TRIE, TopicKey}) of
+    case mnesia:wread({Trie, TopicKey}) of
         [_] -> ok; %% already inserted
-        [] -> lists:foreach(fun insert_key/1, [TopicKey | PrefixKeys])
+        [] -> lists:foreach(fun(Key) -> insert_key(Key, Trie) end, [TopicKey | PrefixKeys])
     end.
 
 %% @doc Delete a topic filter from the trie.
 -spec(delete(emqx_topic:topic()) -> ok).
 delete(Topic) when is_binary(Topic) ->
+    delete(Topic, ?TRIE).
+
+%% @doc Delete a topic filter from the trie.
+-spec(delete_session(emqx_topic:topic()) -> ok).
+delete_session(Topic) when is_binary(Topic) ->
+    delete(Topic, ?SESSION_TRIE).
+
+delete(Topic, Trie) when is_binary(Topic) ->
     {TopicKey, PrefixKeys} = make_keys(Topic),
-    case [] =/= mnesia:wread({?TRIE, TopicKey}) of
-        true -> lists:foreach(fun delete_key/1, [TopicKey | PrefixKeys]);
+    case [] =/= mnesia:wread({Trie, TopicKey}) of
+        true -> lists:foreach(fun(Key) -> delete_key(Key, Trie) end, [TopicKey | PrefixKeys]);
         false -> ok
     end.
 
 %% @doc Find trie nodes that matchs the topic name.
 -spec(match(emqx_topic:topic()) -> list(emqx_topic:topic())).
 match(Topic) when is_binary(Topic) ->
+    match(Topic, ?TRIE).
+
+-spec(match_session(emqx_topic:topic()) -> list(emqx_topic:topic())).
+match_session(Topic) when is_binary(Topic) ->
+    match(Topic, ?SESSION_TRIE).
+
+match(Topic, Trie) when is_binary(Topic) ->
     Words = emqx_topic:words(Topic),
     case emqx_topic:wildcard(Words) of
         true ->
@@ -110,17 +146,26 @@ match(Topic) when is_binary(Topic) ->
             %% Such clients will get disconnected.
             [];
         false ->
-            do_match(Words)
+            do_match(Words, Trie)
     end.
 
 %% @doc Is the trie empty?
 -spec(empty() -> boolean()).
-empty() -> ets:first(?TRIE) =:= '$end_of_table'.
+empty() -> empty(?TRIE).
+
+empty_session() ->
+    empty(?SESSION_TRIE).
+
+empty(Trie) -> ets:first(Trie) =:= '$end_of_table'.
 
 -spec lock_tables() -> ok.
 lock_tables() ->
     mnesia:write_lock_table(?TRIE).
 
+-spec lock_session_tables() -> ok.
+lock_session_tables() ->
+    mnesia:write_lock_table(?SESSION_TRIE).
+
 %%--------------------------------------------------------------------
 %% Internal functions
 %%--------------------------------------------------------------------
@@ -168,70 +213,70 @@ make_prefixes([H | T], Prefix0, Acc0) ->
     Acc = [Prefix | Acc0],
     make_prefixes(T, Prefix, Acc).
 
-insert_key(Key) ->
-    T = case mnesia:wread({?TRIE, Key}) of
+insert_key(Key, Trie) ->
+    T = case mnesia:wread({Trie, Key}) of
             [#?TRIE{count = C} = T1] ->
                 T1#?TRIE{count = C + 1};
              [] ->
                 #?TRIE{key = Key, count = 1}
          end,
-    ok = mnesia:write(T).
+    ok = mnesia:write(Trie, T, write).
 
-delete_key(Key) ->
-    case mnesia:wread({?TRIE, Key}) of
+delete_key(Key, Trie) ->
+    case mnesia:wread({Trie, Key}) of
         [#?TRIE{count = C} = T] when C > 1 ->
-            ok = mnesia:write(T#?TRIE{count = C - 1});
+            ok = mnesia:write(Trie, T#?TRIE{count = C - 1}, write);
         [_] ->
-            ok = mnesia:delete(?TRIE, Key, write);
+            ok = mnesia:delete(Trie, Key, write);
         [] ->
             ok
     end.
 
 %% micro-optimization: no need to lookup when topic is not wildcard
 %% because we only insert wildcards to emqx_trie
-lookup_topic(_Topic, false) -> [];
-lookup_topic(Topic, true) -> lookup_topic(Topic).
+lookup_topic(_Topic,_Trie, false) -> [];
+lookup_topic(Topic, Trie, true) -> lookup_topic(Topic, Trie).
 
-lookup_topic(Topic) when is_binary(Topic) ->
-    case ets:lookup(?TRIE, ?TOPIC(Topic)) of
+lookup_topic(Topic, Trie) when is_binary(Topic) ->
+    case ets:lookup(Trie, ?TOPIC(Topic)) of
         [#?TRIE{count = C}] -> [Topic || C > 0];
         [] -> []
     end.
 
-has_prefix(empty) -> true; %% this is the virtual tree root
-has_prefix(Prefix) ->
-    case ets:lookup(?TRIE, ?PREFIX(Prefix)) of
+has_prefix(empty, _Trie) -> true; %% this is the virtual tree root
+has_prefix(Prefix, Trie) ->
+    case ets:lookup(Trie, ?PREFIX(Prefix)) of
         [#?TRIE{count = C}] -> C > 0;
         [] -> false
     end.
 
-do_match([<<"$", _/binary>> = Prefix | Words]) ->
+do_match([<<"$", _/binary>> = Prefix | Words], Trie) ->
     %% For topics having dollar sign prefix,
     %% we do not match root level + or #,
     %% fast forward to the next level.
     case Words =:= [] of
-        true -> lookup_topic(Prefix);
+        true -> lookup_topic(Prefix, Trie);
         false -> []
-    end ++ do_match(Words, Prefix);
-do_match(Words) ->
-    do_match(Words, empty).
+    end ++ do_match(Words, Prefix, Trie);
+do_match(Words, Trie) ->
+    do_match(Words, empty, Trie).
 
-do_match(Words, Prefix) ->
+do_match(Words, Prefix, Trie) ->
     case is_compact() of
-        true -> match_compact(Words, Prefix, false, []);
-        false -> match_no_compact(Words, Prefix, false, [])
+        true -> match_compact(Words, Prefix, Trie, false, []);
+        false -> match_no_compact(Words, Prefix, Trie, false, [])
     end.
 
-match_no_compact([], Topic, IsWildcard, Acc) ->
-    'match_#'(Topic) ++ %% try match foo/+/# or foo/bar/#
-    lookup_topic(Topic, IsWildcard) ++ %% e.g. foo/+
+match_no_compact([], Topic, Trie, IsWildcard, Acc) ->
+    'match_#'(Topic, Trie) ++ %% try match foo/+/# or foo/bar/#
+    lookup_topic(Topic, Trie, IsWildcard) ++ %% e.g. foo/+
     Acc;
-match_no_compact([Word | Words], Prefix, IsWildcard, Acc0) ->
-    case has_prefix(Prefix) of
+match_no_compact([Word | Words], Prefix, Trie, IsWildcard, Acc0) ->
+    case has_prefix(Prefix, Trie) of
         true ->
-            Acc1 = 'match_#'(Prefix) ++ Acc0,
-            Acc = match_no_compact(Words, join(Prefix, '+'), true, Acc1),
-            match_no_compact(Words, join(Prefix, Word), IsWildcard, Acc);
+            Acc1 = 'match_#'(Prefix, Trie) ++ Acc0,
+            Acc = match_no_compact(Words, join(Prefix, '+'), Trie, true, Acc1),
+            match_no_compact(Words, join(Prefix, Word), Trie, IsWildcard, Acc);
         false ->
             %% non-compact paths in database
             %% if there is no prefix matches the current topic prefix
@@ -248,26 +293,26 @@ match_no_compact([Word | Words], Prefix, IsWildcard, Acc0) ->
             Acc0
     end.
 
-match_compact([], Topic, IsWildcard, Acc) ->
-    'match_#'(Topic) ++ %% try match foo/bar/#
-    lookup_topic(Topic, IsWildcard) ++ %% try match foo/bar
+match_compact([], Topic, Trie, IsWildcard, Acc) ->
+    'match_#'(Topic, Trie) ++ %% try match foo/bar/#
+    lookup_topic(Topic, Trie, IsWildcard) ++ %% try match foo/bar
     Acc;
-match_compact([Word | Words], Prefix, IsWildcard, Acc0) ->
-    Acc1 = 'match_#'(Prefix) ++ Acc0,
-    Acc = match_compact(Words, join(Prefix, Word), IsWildcard, Acc1),
+match_compact([Word | Words], Prefix, Trie, IsWildcard, Acc0) ->
+    Acc1 = 'match_#'(Prefix, Trie) ++ Acc0,
+    Acc = match_compact(Words, join(Prefix, Word), Trie, IsWildcard, Acc1),
     WildcardPrefix = join(Prefix, '+'),
     %% go deeper to match current_prefix/+ only when:
     %% 1. current word is the last
     %% OR
     %% 2. there is a prefix = 'current_prefix/+'
-    case Words =:= [] orelse has_prefix(WildcardPrefix) of
-        true -> match_compact(Words, WildcardPrefix, true, Acc);
+    case Words =:= [] orelse has_prefix(WildcardPrefix, Trie) of
+        true -> match_compact(Words, WildcardPrefix, Trie, true, Acc);
         false -> Acc
     end.
 
-'match_#'(Prefix) ->
+'match_#'(Prefix, Trie) ->
     MlTopic = join(Prefix, '#'),
-    lookup_topic(MlTopic).
+    lookup_topic(MlTopic, Trie).
 
 is_compact() ->
     emqx_config:get([broker, perf, trie_compaction], true).

apps/emqx/test/emqx_channel_SUITE.erl

@@ -191,6 +191,7 @@ init_per_suite(Config) ->
     ok = meck:expect(emqx_hooks, run_fold, fun(_Hook, _Args, Acc) -> Acc end),
     %% Session Meck
     ok = meck:new(emqx_session, [passthrough, no_history, no_link]),
+    meck:expect(emqx_session, db_put, fun(_, _, _) -> ok end),
     %% Metrics
     ok = meck:new(emqx_metrics, [passthrough, no_history, no_link]),
     ok = meck:expect(emqx_metrics, inc, fun(_) -> ok end),

apps/emqx/test/emqx_mqtt_protocol_v5_SUITE.erl

@@ -333,37 +333,6 @@ t_connect_keepalive_timeout(Config) ->
         error("keepalive timeout")
     end.
 
-%% [MQTT-3.1.2-23]
-t_connect_session_expiry_interval(Config) ->
-    ConnFun = ?config(conn_fun, Config),
-    Topic = nth(1, ?TOPICS),
-    Payload = "test message",
-
-    {ok, Client1} = emqtt:start_link([ {clientid, <<"t_connect_session_expiry_interval">>},
-                                       {proto_ver, v5},
-                                       {properties, #{'Session-Expiry-Interval' => 7200}}
-                                       | Config
-                                    ]),
-    {ok, _} = emqtt:ConnFun(Client1),
-    {ok, _, [2]} = emqtt:subscribe(Client1, Topic, qos2),
-    ok = emqtt:disconnect(Client1),
-
-    {ok, Client2} = emqtt:start_link([{proto_ver, v5} | Config]),
-    {ok, _} = emqtt:ConnFun(Client2),
-    {ok, 2} = emqtt:publish(Client2, Topic, Payload, 2),
-    ok = emqtt:disconnect(Client2),
-
-    {ok, Client3} = emqtt:start_link([ {clientid, <<"t_connect_session_expiry_interval">>},
-                                       {proto_ver, v5},
-                                       {clean_start, false} | Config
-                                    ]),
-    {ok, _} = emqtt:ConnFun(Client3),
-    [Msg | _ ] = receive_messages(1),
-    ?assertEqual({ok, iolist_to_binary(Topic)}, maps:find(topic, Msg)),
-    ?assertEqual({ok, iolist_to_binary(Payload)}, maps:find(payload, Msg)),
-    ?assertEqual({ok, 2}, maps:find(qos, Msg)),
-    ok = emqtt:disconnect(Client3).
-
 %% [MQTT-3.1.3-9]
 %% !!!REFACTOR NEED:
 %t_connect_will_delay_interval(Config) ->

apps/emqx/test/emqx_persistent_session_SUITE.erl

@@ -0,0 +1,307 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2020-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_persistent_session_SUITE).
+
+-include_lib("stdlib/include/assert.hrl").
+
+-compile(export_all).
+-compile(nowarn_export_all).
+
+%%--------------------------------------------------------------------
+%% SUITE boilerplate
+%%--------------------------------------------------------------------
+
+all() ->
+    [ {group, tcp}
+    , {group, quic}
+    ].
+
+groups() ->
+    TCs = emqx_ct:all(?MODULE),
+    [ {tcp,  [], TCs}
+    , {quic, [], TCs}
+    ].
+
+init_per_group(tcp, Config) ->
+    emqx_ct_helpers:start_apps([]),
+    [ {port, 1883}, {conn_fun, connect} | Config];
+init_per_group(quic, Config) ->
+    emqx_ct_helpers:start_apps([]),
+    [ {port, 14567}, {conn_fun, quic_connect} | Config];
+init_per_group(_, Config) ->
+    emqx_ct_helpers:stop_apps([]),
+    Config.
+
+init_per_suite(Config) ->
+    %% Start Apps
+    emqx_ct_helpers:boot_modules(all),
+    emqx_ct_helpers:start_apps([emqx], fun set_special_confs/1),
+    Config.
+
+set_special_confs(emqx) ->
+    application:set_env(emqx, plugins_loaded_file,
+                        emqx_ct_helpers:deps_path(emqx, "test/emqx_SUITE_data/loaded_plugins"));
+set_special_confs(_) ->
+    ok.
+
+end_per_suite(_Config) ->
+    emqx_ct_helpers:stop_apps([]).
+
+init_per_testcase(TestCase, Config) ->
+    case erlang:function_exported(?MODULE, TestCase, 2) of
+        true -> ?MODULE:TestCase(init, Config);
+        _ -> Config
+    end.
+
+end_per_testcase(TestCase, Config) ->
+    case erlang:function_exported(?MODULE, TestCase, 2) of
+        true -> ?MODULE:TestCase('end', Config);
+        false -> ok
+    end,
+    Config.
+
+%%--------------------------------------------------------------------
+%% Helpers
+%%--------------------------------------------------------------------
+
+client_info(Key, Client) ->
+    maps:get(Key, maps:from_list(emqtt:info(Client)), undefined).
+
+receive_messages(Count) ->
+    receive_messages(Count, []).
+
+receive_messages(0, Msgs) ->
+    Msgs;
+receive_messages(Count, Msgs) ->
+    receive
+        {publish, Msg} ->
+            receive_messages(Count-1, [Msg|Msgs]);
+        _Other ->
+            receive_messages(Count, Msgs)
+    after 1000 ->
+        Msgs
+    end.
+
+%%--------------------------------------------------------------------
+%% Test Cases
+%%--------------------------------------------------------------------
+
+%% [MQTT-3.1.2-23]
+t_connect_session_expiry_interval(_) ->
+    ConnFun = ?config(conn_fun, Config),
+    Topic = <<"t_connect_session_expiry_interval/foo">>,
+    Payload = "test message",
+
+    {ok, Client1} = emqtt:start_link([ {clientid, <<"t_connect_session_expiry_interval">>},
+                                       {proto_ver, v5},
+                                       {properties, #{'Session-Expiry-Interval' => 7200}}
+                                    ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    {ok, _, [2]} = emqtt:subscribe(Client1, Topic, qos2),
+    ok = emqtt:disconnect(Client1),
+
+    {ok, Client2} = emqtt:start_link([{proto_ver, v5}]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    {ok, 2} = emqtt:publish(Client2, Topic, Payload, 2),
+    ok = emqtt:disconnect(Client2),
+
+    {ok, Client3} = emqtt:start_link([ {clientid, <<"t_connect_session_expiry_interval">>},
+                                       {proto_ver, v5},
+                                       {properties, #{'Session-Expiry-Interval' => 7200}},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client3),
+    [Msg | _ ] = receive_messages(1),
+    ?assertEqual({ok, iolist_to_binary(Topic)}, maps:find(topic, Msg)),
+    ?assertEqual({ok, iolist_to_binary(Payload)}, maps:find(payload, Msg)),
+    ?assertEqual({ok, 2}, maps:find(qos, Msg)),
+    ok = emqtt:disconnect(Client3).
+
+t_without_client_id(_) ->
+    process_flag(trap_exit, true), %% Emqtt client dies
+    {ok, Client0} = emqtt:start_link([ {proto_ver, v5},
+                                       {properties, #{'Session-Expiry-Interval' => 7200}},
+                                       {clean_start, false}
+                                     ]),
+    {error, {client_identifier_not_valid, _}} = emqtt:connect(Client0),
+    ok.
+
+t_assigned_clientid_persistent_session(_) ->
+    ConnFun = ?config(conn_fun, Config),
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {properties, #{'Session-Expiry-Interval' => 7200}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+
+    AssignedClientId = client_info(clientid, Client1),
+    ok = emqtt:disconnect(Client1),
+
+    {ok, Client2} = emqtt:start_link([ {clientid, AssignedClientId},
+                                       {proto_ver, v5},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    ?assertEqual(1, client_info(session_present, Client2)),
+    ok = emqtt:disconnect(Client2).
+
+t_cancel_on_disconnect(_) ->
+    ConnFun = ?config(conn_fun, Config),
+    ClientId = <<"t_cancel_on_disconnect">>,
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 16#FFFFFFFF}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    ok = emqtt:disconnect(Client1, 0, #{'Session-Expiry-Interval' => 0}),
+
+    {ok, Client2} = emqtt:start_link([ {clientid, ClientId},
+                                       {proto_ver, v5},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    ?assertEqual(0, client_info(session_present, Client2)),
+    ok = emqtt:disconnect(Client2).
+
+t_process_dies(_) ->
+    %% Emulate an error in the connect process,
+    %% or that the node of the process goes down.
+    %% A persistent session should survive anyway.
+    ConnFun = ?config(conn_fun, Config),
+    ClientId = <<"t_process_dies">>,
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 16#FFFFFFFF}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    ok = emqtt:disconnect(Client1),
+
+    [ChannelPid] = emqx_cm:lookup_channels(ClientId),
+    ?assert(is_pid(ChannelPid)),
+    exit(ChannelPid, kill),
+
+    {ok, Client2} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    ?assertEqual(1, client_info(session_present, Client2)),
+    emqtt:disconnect(Client2).
+
+t_process_dies_session_expires(_) ->
+    %% Emulate an error in the connect process,
+    %% or that the node of the process goes down.
+    %% A persistent session should eventually expire.
+    ConnFun = ?config(conn_fun, Config),
+    ClientId = <<"t_process_dies_session_expires">>,
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 1}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    ok = emqtt:disconnect(Client1),
+
+    [ChannelPid] = emqx_cm:lookup_channels(ClientId),
+    ?assert(is_pid(ChannelPid)),
+    exit(ChannelPid, kill),
+
+    timer:sleep(1000),
+
+    {ok, Client2} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    ?assertEqual(0, client_info(session_present, Client2)),
+    emqtt:disconnect(Client2).
+
+t_clean_start_drops_subscriptions(_) ->
+    ConnFun = ?config(conn_fun, Config),
+    Topic = <<"t_clean_start_drops_subscriptions/bar">>,
+    STopic = <<"t_clean_start_drops_subscriptions/+">>,
+    Payload = <<"hello">>,
+    ClientId = <<"t_clean_start_drops_subscriptions">>,
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 30}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    {ok, _, [0]} = emqtt:subscribe(Client1, STopic, 0),
+    ok = emqtt:disconnect(Client1),
+
+    {ok, Client2} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    ?assertEqual(0, client_info(session_present, Client2)),
+    {ok, _, [0]} = emqtt:subscribe(Client2, STopic, 0),
+
+    {ok, Client3} = emqtt:start_link([{proto_ver, v5}]),
+    {ok, _} = emqtt:ConnFun(Client3),
+    {ok, 2} = emqtt:publish(Client3, Topic, Payload, 2),
+    ok = emqtt:disconnect(Client3),
+
+    [_Msg1] = receive_messages(1),
+
+    ok = emqtt:disconnect(Client2).
+
+t_subscription_while_process_is_gone(_) ->
+    ConnFun = ?config(conn_fun, Config),
+    Topic = <<"t_clean_start_drops_subscriptions/bar">>,
+    STopic = <<"t_clean_start_drops_subscriptions/+">>,
+    Payload1 = <<"hello1">>,
+    Payload2 = <<"hello2">>,
+    ClientId = <<"t_clean_start_drops_subscriptions">>,
+    {ok, Client1} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 30}},
+                                       {clean_start, true}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client1),
+    {ok, _, [2]} = emqtt:subscribe(Client1, STopic, 2),
+    ok = emqtt:disconnect(Client1),
+
+    [ChannelPid] = emqx_cm:lookup_channels(ClientId),
+    ?assert(is_pid(ChannelPid)),
+    exit(ChannelPid, kill),
+
+    {ok, Client2} = emqtt:start_link([]),
+    {ok, _} = emqtt:ConnFun(Client2),
+    {ok, 2} = emqtt:publish(Client2, Topic, Payload1, 2),
+    {ok, 3} = emqtt:publish(Client2, Topic, Payload2, 2),
+
+    {ok, Client3} = emqtt:start_link([ {proto_ver, v5},
+                                       {clientid, ClientId},
+                                       {properties, #{'Session-Expiry-Interval' => 30}},
+                                       {clean_start, false}
+                                     ]),
+    {ok, _} = emqtt:ConnFun(Client3),
+    [Msg1] = receive_messages(1),
+    [Msg2] = receive_messages(1),
+    ?assertEqual({ok, iolist_to_binary(Payload1)}, maps:find(payload, Msg1)),
+    ?assertEqual({ok, 2}, maps:find(qos, Msg1)),
+    ?assertEqual({ok, iolist_to_binary(Payload2)}, maps:find(payload, Msg2)),
+    ?assertEqual({ok, 2}, maps:find(qos, Msg2)),
+
+    ok = emqtt:disconnect(Client2),
+    ok = emqtt:disconnect(Client3).
+

apps/emqx/test/emqx_trie_SUITE.erl

@@ -186,7 +186,7 @@ t_delete3(_) ->
               ?TRIE:delete(<<"sensor/+/unknown">>)
           end),
     ?assertEqual([], ?TRIE:match(<<"sensor">>)),
-    ?assertEqual([], ?TRIE:lookup_topic(<<"sensor/+">>)).
+    ?assertEqual([], ?TRIE:lookup_topic(<<"sensor/+">>, ?TRIE)).
 
 clear_tables() -> emqx_trie:clear_tables().