diff --git a/CHANGES-4.3.md b/CHANGES-4.3.md
index ef1498aff..673dbef8a 100644
--- a/CHANGES-4.3.md
+++ b/CHANGES-4.3.md
@@ -18,6 +18,11 @@ File format:
 
 ## v4.3.21
 
+### Bug fixes
+
+- Deny POST an existing resource id using HTTP API with error 400 "Already Exists". [#9079](https://github.com/emqx/emqx/pull/9079)
+- Fix the issue that reseting rule metrics crashed under certain conditions. [#9079](https://github.com/emqx/emqx/pull/9079)
+
 ### Enhancements
 
 - TLS listener memory usage optimization [#9005](https://github.com/emqx/emqx/pull/9005).
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src b/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
index 6aa35d2d6..b46be85c7 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
@@ -3,17 +3,20 @@
 {VSN,
   [{"4.3.15",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]}]},
    {"4.3.14",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_runtime,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]}]},
    {"4.3.13",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
@@ -22,6 +25,7 @@
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]}]},
    {"4.3.12",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
@@ -30,6 +34,7 @@
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]}]},
    {"4.3.11",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
@@ -39,6 +44,7 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {"4.3.10",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_validator,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
@@ -48,6 +54,7 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {"4.3.9",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_validator,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
@@ -200,17 +207,20 @@
    {<<".*">>,[]}],
   [{"4.3.15",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]}]},
    {"4.3.14",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_runtime,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]}]},
    {"4.3.13",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
@@ -219,6 +229,7 @@
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]}]},
    {"4.3.12",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
@@ -227,6 +238,7 @@
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]}]},
    {"4.3.11",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
@@ -236,6 +248,7 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {"4.3.10",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_validator,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
@@ -245,6 +258,7 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {"4.3.9",
     [{load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_metrics,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_validator,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_actions,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
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 50fdcfe22..ea0a13824 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
@@ -306,7 +306,7 @@ show_action(#{name := Name}, _Params) ->
 create_resource(#{}, Params) ->
     case parse_resource_params(Params) of
         {ok, ParsedParams} ->
-            if_test(fun() -> do_create_resource(test_resource, ParsedParams) end,
+            if_test(fun() -> do_create_resource(test_resource, maps:without([id], ParsedParams)) end,
                     fun() -> do_create_resource(create_resource, ParsedParams) end,
                     Params);
         {error, Reason} ->
@@ -315,6 +315,16 @@ create_resource(#{}, Params) ->
     end.
 
 do_create_resource(Create, ParsedParams) ->
+    case maps:find(id, ParsedParams) of
+        {ok, ResId} ->
+            case emqx_rule_registry:find_resource(ResId) of
+                {ok, _} -> return({error, 400, <<"Already Exists">>});
+                not_found -> do_create_resource2(Create, ParsedParams)
+            end;
+        error -> do_create_resource2(Create, ParsedParams)
+    end.
+
+do_create_resource2(Create, ParsedParams) ->
     case emqx_rule_engine:Create(ParsedParams) of
         ok ->
             return(ok);
diff --git a/apps/emqx_rule_engine/src/emqx_rule_metrics.erl b/apps/emqx_rule_engine/src/emqx_rule_metrics.erl
index 624032056..e8a77e0db 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_metrics.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_metrics.erl
@@ -328,6 +328,8 @@ handle_call({create_rule_metrics, Id}, _From,
                                     _ -> RuleSpeeds#{Id => #rule_speed{}}
                                 end}};
 
+handle_call({reset_speeds, _Id}, _From, State = #state{rule_speeds = undefined}) ->
+    {reply, ok, State};
 handle_call({reset_speeds, Id}, _From, State = #state{rule_speeds = RuleSpeedMap}) ->
     {reply, ok, State#state{rule_speeds = maps:put(Id, #rule_speed{}, RuleSpeedMap)}};
 
diff --git a/apps/emqx_rule_engine/test/emqx_rule_engine_SUITE.erl b/apps/emqx_rule_engine/test/emqx_rule_engine_SUITE.erl
index c8f66ea00..dc95c0368 100644
--- a/apps/emqx_rule_engine/test/emqx_rule_engine_SUITE.erl
+++ b/apps/emqx_rule_engine/test/emqx_rule_engine_SUITE.erl
@@ -600,13 +600,18 @@ t_show_action_api(_Config) ->
     ok.
 
 t_crud_resources_api(_Config) ->
+    ResParams = [
+        {<<"name">>, <<"Simple Resource">>},
+        {<<"type">>, <<"built_in">>},
+        {<<"config">>, [{<<"a">>, 1}]},
+        {<<"description">>, <<"Simple Resource">>}
+    ],
     {ok, #{code := 0, data := Resources1}} =
-        emqx_rule_engine_api:create_resource(#{},
-            [{<<"name">>, <<"Simple Resource">>},
-             {<<"type">>, <<"built_in">>},
-             {<<"config">>, [{<<"a">>, 1}]},
-             {<<"description">>, <<"Simple Resource">>}]),
+        emqx_rule_engine_api:create_resource(#{}, ResParams),
     ResId = maps:get(id, Resources1),
+    %% create again using given resource id returns error
+    {ok, #{code := 400, message := <<"Already Exists">>}} =
+        emqx_rule_engine_api:create_resource(#{}, [{<<"id">>, ResId} | ResParams]),
     {ok, #{code := 0, data := Resources}} = emqx_rule_engine_api:list_resources(#{}, []),
     ?assert(length(Resources) > 0),
     {ok, #{code := 0, data := Resources2}} = emqx_rule_engine_api:show_resource(#{id => ResId}, []),