diff --git a/apps/emqx_rule_engine/include/rule_engine.hrl b/apps/emqx_rule_engine/include/rule_engine.hrl
index 39c4daf69..49024bada 100644
--- a/apps/emqx_rule_engine/include/rule_engine.hrl
+++ b/apps/emqx_rule_engine/include/rule_engine.hrl
@@ -82,7 +82,7 @@
         { id :: resource_id()
         , type :: resource_type_name()
         , config :: #{} %% the configs got from API for initializing resource
-        , created_at :: erlang:timestamp()
+        , created_at :: integer() %% epoch in millisecond precision
         , description :: binary()
         }).
 
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine.erl b/apps/emqx_rule_engine/src/emqx_rule_engine.erl
index 315637a12..fc40ff38e 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine.erl
@@ -39,6 +39,7 @@
         , get_resource_status/1
         , get_resource_params/1
         , delete_resource/1
+        , ensure_resource_deleted/1
         ]).
 
 -export([ init_resource/4
@@ -154,7 +155,7 @@ module_attributes(Module) ->
 %% APIs for rules and resources
 %%------------------------------------------------------------------------------
 
--dialyzer([{nowarn_function, create_rule/1}]).
+-dialyzer([{nowarn_function, [create_rule/1, rule_id/0]}]).
 -spec(create_rule(#{}) -> {ok, rule()} | no_return()).
 create_rule(Params = #{rawsql := Sql, actions := Actions}) ->
     case emqx_rule_sqlparser:parse_select(Sql) of
@@ -179,7 +180,7 @@ create_rule(Params = #{rawsql := Sql, actions := Actions}) ->
         Error -> error(Error)
     end.
 
--spec(update_rule(#{id := binary(), _=>_}) -> {ok, rule()} | no_return()).
+-spec(update_rule(#{id := binary(), _=>_}) -> {ok, rule()} | {error, {not_found, rule_id()}}).
 update_rule(Params = #{id := RuleId}) ->
     case emqx_rule_registry:get_rule(RuleId) of
         {ok, Rule0} ->
@@ -206,7 +207,7 @@ delete_rule(RuleId) ->
             ok
     end.
 
--spec(create_resource(#{}) -> {ok, resource()} | {error, Reason :: term()}).
+-spec(create_resource(#{type := _, config := _, _ => _}) -> {ok, resource()} | {error, Reason :: term()}).
 create_resource(#{type := Type, config := Config} = Params) ->
     case emqx_rule_registry:find_resource_type(Type) of
         {ok, #resource_type{on_create = {M, F}, params_spec = ParamSpec}} ->
@@ -215,7 +216,9 @@ create_resource(#{type := Type, config := Config} = Params) ->
             Resource = #resource{id = ResId,
                                  type = Type,
                                  config = Config,
-                                 description = iolist_to_binary(maps:get(description, Params, ""))},
+                                 description = iolist_to_binary(maps:get(description, Params, "")),
+                                 created_at = erlang:system_time(millisecond)
+                                },
             ok = emqx_rule_registry:add_resource(Resource),
             %% Note that we will return OK in case of resource creation failure,
             %% users can always re-start the resource later.
@@ -231,14 +234,14 @@ start_resource(ResId) ->
         {ok, #resource{type = ResType, config = Config}} ->
             {ok, #resource_type{on_create = {Mod, Create}}}
                 = emqx_rule_registry:find_resource_type(ResType),
-            init_resource(Mod, Create, ResId, Config),
+            _ = init_resource(Mod, Create, ResId, Config),
             refresh_actions_of_a_resource(ResId),
             ok;
         not_found ->
             {error, {resource_not_found, ResId}}
     end.
 
--spec(test_resource(#{}) -> ok | {error, Reason :: term()}).
+-spec(test_resource(#{type := _, config := _, _ => _}) -> ok | {error, Reason :: term()}).
 test_resource(#{type := Type, config := Config}) ->
     case emqx_rule_registry:find_resource_type(Type) of
         {ok, #resource_type{on_create = {ModC,Create}, on_destroy = {ModD,Destroy}, params_spec = ParamSpec}} ->
@@ -284,6 +287,12 @@ delete_resource(ResId) ->
             {error, {resource_not_found, ResId}}
     end.
 
+%% @doc Ensure resource deleted. `resource_not_found` error is discarded.
+-spec(ensure_resource_deleted(resource_id()) -> ok).
+ensure_resource_deleted(ResId) ->
+    _ = delete_resource(ResId),
+    ok.
+
 %%------------------------------------------------------------------------------
 %% Re-establish resources
 %%------------------------------------------------------------------------------
@@ -530,12 +539,12 @@ fetch_resource_status(Module, OnStatus, ResId) ->
     end.
 
 refresh_actions_of_a_resource(ResId) ->
-    [refresh_actions(Actions,
-        fun (#action_instance{args = #{<<"$resource">> := ResId0}})
+    R = fun (#action_instance{args = #{<<"$resource">> := ResId0}})
                 when ResId0 =:= ResId -> true;
             (_) -> false
-        end)
-     || #rule{actions = Actions} <- emqx_rule_registry:get_rules()].
+        end,
+    F = fun(#rule{actions = Actions}) -> refresh_actions(Actions, R) end,
+    lists:foreach(F, emqx_rule_registry:get_rules()).
 
 refresh_actions(Actions) ->
     refresh_actions(Actions, fun(_) -> true end).
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
index 2a6ad1754..131ea9651 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
@@ -355,7 +355,7 @@ start_resource(#{id := Id}, _Params) ->
 
 delete_resource(#{id := Id}, _Params) ->
     try
-        emqx_rule_engine:delete_resource(Id),
+        ok = emqx_rule_engine:ensure_resource_deleted(Id),
         return(ok)
     catch
         _Error:{throw,Reason} ->