fix(retainer): change mnesia table storage types during update

https://emqx.atlassian.net/browse/EMQX-8650

apps/emqx_retainer/src/emqx_retainer.app.src

@@ -2,7 +2,7 @@
 {application, emqx_retainer, [
     {description, "EMQX Retainer"},
     % strict semver, bump manually!
-    {vsn, "5.0.8"},
+    {vsn, "5.0.9"},
     {modules, []},
     {registered, [emqx_retainer_sup]},
     {applications, [kernel, stdlib, emqx]},

apps/emqx_retainer/src/emqx_retainer.erl

@@ -321,16 +321,23 @@ update_config(
     OldConf
 ) ->
     #{
-        backend := BackendCfg,
+        backend := #{
+            type := BackendType,
+            storage_type := StorageType
+        },
         msg_clear_interval := ClearInterval
     } = NewConf,
 
-    #{backend := OldBackendCfg} = OldConf,
-
-    StorageType = maps:get(type, BackendCfg),
-    OldStrorageType = maps:get(type, OldBackendCfg),
-    case OldStrorageType of
-        StorageType ->
+    #{
+        backend := #{
+            type := OldBackendType,
+            storage_type := OldStorageType
+        }
+    } = OldConf,
+    SameBackendType = BackendType =:= OldBackendType,
+    SameStorageType = StorageType =:= OldStorageType,
+    case SameBackendType andalso SameStorageType of
+        true ->
             State#{
                 clear_timer := check_timer(
                     ClearTimer,
@@ -338,7 +345,7 @@ update_config(
                     clear_expired
                 )
             };
-        _ ->
+        false ->
             State2 = disable_retainer(State),
             enable_retainer(State2, NewConf)
     end.

apps/emqx_retainer/test/emqx_retainer_api_SUITE.erl

@@ -31,6 +31,7 @@ all() ->
     emqx_common_test_helpers:all(?MODULE).
 
 init_per_suite(Config) ->
+    emqx_common_test_helpers:clear_screen(),
     application:load(emqx_conf),
     ok = ekka:start(),
     ok = mria_rlog:wait_for_shards([?CLUSTER_RPC_SHARD], infinity),
@@ -219,6 +220,56 @@ t_lookup_and_delete(_) ->
 
     ok = emqtt:disconnect(C1).
 
+t_change_storage_type(_Config) ->
+    Path = api_path(["mqtt", "retainer"]),
+    {ok, ConfJson} = request_api(get, Path),
+    RawConf = emqx_json:decode(ConfJson, [return_maps]),
+    %% pre-conditions
+    ?assertMatch(
+        #{
+            <<"backend">> := #{
+                <<"type">> := <<"built_in_database">>,
+                <<"storage_type">> := <<"ram">>
+            },
+            <<"enable">> := true
+        },
+        RawConf
+    ),
+    ?assertEqual(ram_copies, mnesia:table_info(?TAB_INDEX_META, storage_type)),
+    ?assertEqual(ram_copies, mnesia:table_info(?TAB_MESSAGE, storage_type)),
+    ?assertEqual(ram_copies, mnesia:table_info(?TAB_INDEX, storage_type)),
+
+    ChangedConf = emqx_map_lib:deep_merge(
+        RawConf,
+        #{
+            <<"backend">> =>
+                #{<<"storage_type">> => <<"disc">>}
+        }
+    ),
+    {ok, UpdateResJson} = request_api(
+        put,
+        Path,
+        [],
+        auth_header_(),
+        ChangedConf
+    ),
+    UpdatedRawConf = emqx_json:decode(UpdateResJson, [return_maps]),
+    ?assertMatch(
+        #{
+            <<"backend">> := #{
+                <<"type">> := <<"built_in_database">>,
+                <<"storage_type">> := <<"disc">>
+            },
+            <<"enable">> := true
+        },
+        UpdatedRawConf
+    ),
+    ?assertEqual(disc_copies, mnesia:table_info(?TAB_INDEX_META, storage_type)),
+    ?assertEqual(disc_copies, mnesia:table_info(?TAB_MESSAGE, storage_type)),
+    ?assertEqual(disc_copies, mnesia:table_info(?TAB_INDEX, storage_type)),
+
+    ok.
+
 %%--------------------------------------------------------------------
 %% HTTP Request
 %%--------------------------------------------------------------------

changes/v5.0.14-en.md

@@ -14,3 +14,5 @@
 - Fix an issue where testing the GCP PubSub could leak memory, and an issue where its JWT token would fail to refresh a second time. [#9641](https://github.com/emqx/emqx/pull/9641)
 
 - Fix the problem of data loss and bad match when the MySQL driver is disconnected [#9638](https://github.com/emqx/emqx/pull/9638).
+
+- Fixed an issue where changing the storage type of the built-in database retainer would not take effect without restarting the node [#9676](https://github.com/emqx/emqx/pull/9676).

changes/v5.0.14-zh.md

@@ -14,3 +14,5 @@
 - 修复了测试GCP PubSub可能泄露内存的问题，以及其JWT令牌第二次刷新失败的问题。 [#9640](https://github.com/emqx/emqx/pull/9640)
 
 - 修复 MySQL 驱动断开连接时出现的数据丢失和匹配错误的问题 [#9638](https://github.com/emqx/emqx/pull/9638)。
+
+- 修复了如果不重新启动节点，改变保留消息的存储类型将不会生效的问题 [#9676](https://github.com/emqx/emqx/pull/9676)。