diff --git a/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl b/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
index 91936c8f0..5bee4ed93 100644
--- a/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
+++ b/apps/emqx/src/emqx_limiter/src/emqx_limiter_schema.erl
@@ -19,7 +19,8 @@
 -include_lib("typerefl/include/types.hrl").
 
 -export([ roots/0, fields/1, to_rate/1, to_capacity/1
-        , minimum_period/0, to_burst_rate/1, to_initial/1]).
+        , minimum_period/0, to_burst_rate/1, to_initial/1
+        , namespace/0]).
 
 -define(KILOBYTE, 1024).
 
@@ -56,6 +57,8 @@
 
 -import(emqx_schema, [sc/2, map/2]).
 
+namespace() -> limiter.
+
 roots() -> [limiter].
 
 fields(limiter) ->
diff --git a/apps/emqx_retainer/src/emqx_retainer_schema.erl b/apps/emqx_retainer/src/emqx_retainer_schema.erl
index 308fc528f..f4c1e54e5 100644
--- a/apps/emqx_retainer/src/emqx_retainer_schema.erl
+++ b/apps/emqx_retainer/src/emqx_retainer_schema.erl
@@ -2,10 +2,12 @@
 
 -include_lib("typerefl/include/types.hrl").
 
--export([roots/0, fields/1]).
+-export([roots/0, fields/1, namespace/0]).
 
 -define(TYPE(Type), hoconsc:mk(Type)).
 
+namespace() -> "retainer".
+
 roots() -> ["retainer"].
 
 fields("retainer") ->
diff --git a/apps/emqx_slow_subs/src/emqx_slow_subs_schema.erl b/apps/emqx_slow_subs/src/emqx_slow_subs_schema.erl
index 2eca0e730..7a1b57d0b 100644
--- a/apps/emqx_slow_subs/src/emqx_slow_subs_schema.erl
+++ b/apps/emqx_slow_subs/src/emqx_slow_subs_schema.erl
@@ -2,7 +2,9 @@
 
 -include_lib("typerefl/include/types.hrl").
 
--export([roots/0, fields/1]).
+-export([roots/0, fields/1, namespace/0]).
+
+namespace() -> "slow_subs".
 
 roots() -> ["slow_subs"].