diff --git a/apps/emqx_modules/src/emqx_delayed.erl b/apps/emqx_modules/src/emqx_delayed.erl
index 05b65516c..db6226c1f 100644
--- a/apps/emqx_modules/src/emqx_delayed.erl
+++ b/apps/emqx_modules/src/emqx_delayed.erl
@@ -55,6 +55,7 @@
 -export([format_delayed/1]).
 
 -record(delayed_message, {key, delayed, msg}).
+-type delayed_message() :: #delayed_message{}.
 
 %% sync ms with record change
 -define(QUERY_MS(Id), [{{delayed_message, {'_', Id}, '_', '_'}, [], ['$_']}]).
@@ -116,7 +117,7 @@ start_link() ->
     Opts = emqx_conf:get([delayed], #{}),
     gen_server:start_link({local, ?SERVER}, ?MODULE, [Opts], []).
 
--spec(store(#delayed_message{}) -> ok | {error, atom()}).
+-spec(store(delayed_message()) -> ok | {error, atom()}).
 store(DelayedMsg) ->
     gen_server:call(?SERVER, {store, DelayedMsg}, infinity).
 
@@ -273,14 +274,15 @@ handle_info({timeout, TRef, do_publish}, State = #{timer := TRef}) ->
     {noreply, ensure_publish_timer(State#{timer := undefined, publish_at := 0})};
 
 handle_info(stats, State = #{stats_fun := StatsFun}) ->
+    StatsTimer = erlang:send_after(timer:seconds(1), self(), stats),
     StatsFun(delayed_count()),
-    {noreply, State, hibernate};
+    {noreply, State#{stats_timer := StatsTimer}, hibernate};
 
 handle_info(Info, State) ->
     ?SLOG(error, #{msg => "unexpected_info", info => Info}),
     {noreply, State}.
 
-terminate(_Reason, #{timer := TRef}) ->
+terminate(_Reason, #{stats_timer := TRef}) ->
     emqx_conf:remove_handler([delayed]),
     emqx_misc:cancel_timer(TRef).
 
@@ -294,7 +296,7 @@ code_change(_Vsn, State, _Extra) ->
 %% Ensure the stats
 ensure_stats_event(State) ->
     StatsFun = emqx_stats:statsfun('delayed.count', 'delayed.max'),
-    {ok, StatsTimer} = timer:send_interval(timer:seconds(1), stats),
+    StatsTimer = erlang:send_after(timer:seconds(1), self(), stats),
     State#{stats_fun => StatsFun, stats_timer => StatsTimer}.
 
 %% Ensure publish timer
@@ -331,7 +333,7 @@ do_publish(Key = {Ts, _Id}, Now, Acc) when Ts =< Now ->
         [#delayed_message{msg = Msg}] ->
             emqx_pool:async_submit(fun emqx:publish/1, [Msg])
     end,
-    do_publish(mnesia:dirty_next(?TAB, Key), Now, [Key|Acc]).
+    do_publish(mnesia:dirty_next(?TAB, Key), Now, [Key | Acc]).
 
 -spec(delayed_count() -> non_neg_integer()).
 delayed_count() -> mnesia:table_info(?TAB, size).