fix(persistent_sessions): Add both disc and ram tables to avoid schema confusion

apps/emqx/src/emqx_persistent_session.erl

@@ -82,14 +82,14 @@
 init_db_backend() ->
     case is_store_enabled() of
         true  ->
-            TableType =
+            Backend =
                 case emqx_config:get(?db_backend_key) of
-                    mnesia_ram -> ram_copies;
-                    mnesia_disc -> disc_copies
+                    mnesia_ram  -> emqx_persistent_session_mnesia_ram_backend;
+                    mnesia_disc -> emqx_persistent_session_mnesia_disc_backend
                 end,
-            ok = emqx_trie:create_session_trie(TableType),
-            emqx_persistent_session_mnesia_backend:create_tables(TableType),
-            persistent_term:put(?db_backend_module, emqx_persistent_session_mnesia_backend),
+            persistent_term:put(?db_backend_module, Backend),
+            Backend:create_tables(),
+            ok = emqx_trie:create_session_trie(),
             ok;
         false ->
             persistent_term:put(?db_backend_module, emqx_persistent_session_dummy_backend),

apps/emqx/src/emqx_persistent_session.hrl

@@ -14,10 +14,6 @@
 %% limitations under the License.
 %%--------------------------------------------------------------------
 
--define(SESSION_STORE, emqx_session_store).
--define(SESS_MSG_TAB, emqx_session_msg).
--define(MSG_TAB, emqx_persistent_msg).
-
 -record(session_store, { client_id        :: binary()
                        , expiry_interval  :: non_neg_integer()
                        , ts               :: non_neg_integer()

apps/emqx/src/emqx_persistent_session_mnesia_disc_backend.erl

@@ -0,0 +1,114 @@
+%%--------------------------------------------------------------------
+%% Copyright (c) 2021 EMQ Technologies Co., Ltd. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%--------------------------------------------------------------------
+
+-module(emqx_persistent_session_mnesia_disc_backend).
+
+-include("emqx.hrl").
+-include("emqx_persistent_session.hrl").
+
+-define(SESSION_STORE, emqx_session_store_disc).
+-define(SESS_MSG_TAB, emqx_session_msg_disc).
+-define(MSG_TAB, emqx_persistent_msg_disc).
+
+-export([ create_tables/0
+        , first_message_id/0
+        , next_message_id/1
+        , delete_message/1
+        , first_session_message/0
+        , next_session_message/1
+        , delete_session_message/1
+        , put_session_store/1
+        , delete_session_store/1
+        , lookup_session_store/1
+        , put_session_message/1
+        , put_message/1
+        , get_message/1
+        , ro_transaction/1
+        ]).
+
+create_tables() ->
+    ok = mria:create_table(?SESSION_STORE, [
+                {type, set},
+                {rlog_shard, ?PERSISTENT_SESSION_SHARD},
+                {storage, disc_copies},
+                {record_name, session_store},
+                {attributes, record_info(fields, session_store)},
+                {storage_properties, [{ets, [{read_concurrency, true}]}]}]),
+
+    ok = mria:create_table(?SESS_MSG_TAB, [
+                {type, ordered_set},
+                {rlog_shard, ?PERSISTENT_SESSION_SHARD},
+                {storage, disc_copies},
+                {record_name, session_msg},
+                {attributes, record_info(fields, session_msg)},
+                {storage_properties, [{ets, [{read_concurrency, true},
+                                             {write_concurrency, true}]}]}]),
+
+    ok = mria:create_table(?MSG_TAB, [
+                {type, ordered_set},
+                {rlog_shard, ?PERSISTENT_SESSION_SHARD},
+                {storage, disc_copies},
+                {record_name, message},
+                {attributes, record_info(fields, message)},
+                {storage_properties, [{ets, [{read_concurrency, true},
+                                             {write_concurrency, true}]}]}]).
+
+first_session_message() ->
+    mnesia:dirty_first(?SESS_MSG_TAB).
+
+next_session_message(Key) ->
+    mnesia:dirty_next(?SESS_MSG_TAB, Key).
+
+first_message_id() ->
+    mnesia:dirty_first(?MSG_TAB).
+
+next_message_id(Key) ->
+    mnesia:dirty_next(?MSG_TAB, Key).
+
+delete_message(Key) ->
+    mria:dirty_delete(?MSG_TAB, Key).
+
+delete_session_message(Key) ->
+    mria:dirty_delete(?SESS_MSG_TAB, Key).
+
+put_session_store(SS) ->
+    mria:dirty_write(?SESSION_STORE, SS).
+
+delete_session_store(ClientID) ->
+    mria:dirty_delete(?SESSION_STORE, ClientID).
+
+lookup_session_store(ClientID) ->
+    case mnesia:dirty_read(?SESSION_STORE, ClientID) of
+        [] -> none;
+        [SS] -> {value, SS}
+    end.
+
+put_session_message(SessMsg) ->
+    mria:dirty_write(?SESS_MSG_TAB, SessMsg).
+
+put_message(Msg) ->
+    mria:dirty_write(?MSG_TAB, Msg).
+
+get_message(MsgId) ->
+    case mnesia:read(?MSG_TAB, MsgId) of
+        [] -> error({msg_not_found, MsgId});
+        [Msg] -> Msg
+    end.
+
+ro_transaction(Fun) ->
+    {atomic, Res} = mria:ro_transaction(?PERSISTENT_SESSION_SHARD, Fun),
+    Res.
+

apps/emqx/src/emqx_persistent_session_mnesia_ram_backend.erl

@@ -14,12 +14,16 @@
 %% limitations under the License.
 %%--------------------------------------------------------------------
 
--module(emqx_persistent_session_mnesia_backend).
+-module(emqx_persistent_session_mnesia_ram_backend).
 
 -include("emqx.hrl").
 -include("emqx_persistent_session.hrl").
 
--export([ create_tables/1
+-define(SESSION_STORE, emqx_session_store_ram).
+-define(SESS_MSG_TAB, emqx_session_msg_ram).
+-define(MSG_TAB, emqx_persistent_msg_ram).
+
+-export([ create_tables/0
         , first_message_id/0
         , next_message_id/1
         , delete_message/1
@@ -35,12 +39,11 @@
         , ro_transaction/1
         ]).
 
-create_tables(TableType) when TableType =:= ram_copies;
-                              TableType =:= disc_copies ->
+create_tables() ->
     ok = mria:create_table(?SESSION_STORE, [
                 {type, set},
                 {rlog_shard, ?PERSISTENT_SESSION_SHARD},
-                {storage, TableType},
+                {storage, ram_copies},
                 {record_name, session_store},
                 {attributes, record_info(fields, session_store)},
                 {storage_properties, [{ets, [{read_concurrency, true}]}]}]),
@@ -48,7 +51,7 @@ create_tables(TableType) when TableType =:= ram_copies;
     ok = mria:create_table(?SESS_MSG_TAB, [
                 {type, ordered_set},
                 {rlog_shard, ?PERSISTENT_SESSION_SHARD},
-                {storage, TableType},
+                {storage, ram_copies},
                 {record_name, session_msg},
                 {attributes, record_info(fields, session_msg)},
                 {storage_properties, [{ets, [{read_concurrency, true},
@@ -57,7 +60,7 @@ create_tables(TableType) when TableType =:= ram_copies;
     ok = mria:create_table(?MSG_TAB, [
                 {type, ordered_set},
                 {rlog_shard, ?PERSISTENT_SESSION_SHARD},
-                {storage, TableType},
+                {storage, ram_copies},
                 {record_name, message},
                 {attributes, record_info(fields, message)},
                 {storage_properties, [{ets, [{read_concurrency, true},

apps/emqx/src/emqx_trie.erl

@@ -17,10 +17,11 @@
 -module(emqx_trie).
 
 -include("emqx.hrl").
+-include("emqx_persistent_session.hrl").
 
 %% Mnesia bootstrap
 -export([ mnesia/1
-        , create_session_trie/1
+        , create_session_trie/0
         ]).
 
 -boot_mnesia({mnesia, [boot]}).
@@ -48,7 +49,8 @@
 -endif.
 
 -define(TRIE, emqx_trie).
--define(SESSION_TRIE, emqx_session_trie).
+-define(SESSION_TRIE_RAM, emqx_session_trie_ram).
+-define(SESSION_TRIE_DISC, emqx_session_trie_disc).
 -define(PREFIX(Prefix), {Prefix, 0}).
 -define(TOPIC(Topic), {Topic, 1}).
 
@@ -57,6 +59,12 @@
         , count = 0 :: non_neg_integer()
         }).
 
+-define(ACTIVE_SESSION_TRIE, case emqx_config:get(?db_backend_key) of
+                                 mnesia_ram  -> ?SESSION_TRIE_RAM;
+                                 mnesia_disc -> ?SESSION_TRIE_DISC
+                             end).
+
+
 %%--------------------------------------------------------------------
 %% Mnesia bootstrap
 %%--------------------------------------------------------------------
@@ -75,19 +83,26 @@ mnesia(boot) ->
                 {type, ordered_set},
                 {storage_properties, StoreProps}]).
 
-create_session_trie(TableType) when TableType =:= ram_copies;
-                                    TableType =:= disc_copies ->
+create_session_trie() ->
     StoreProps = [{ets, [{read_concurrency, true},
                          {write_concurrency, true}
                         ]}],
-    ok = mria:create_table(?SESSION_TRIE,
+    ok = mria:create_table(?SESSION_TRIE_RAM,
                            [{rlog_shard, ?ROUTE_SHARD},
-                            {storage, TableType},
+                            {storage, ram_copies},
+                            {record_name, ?TRIE},
+                            {attributes, record_info(fields, ?TRIE)},
+                            {type, ordered_set},
+                            {storage_properties, StoreProps}]),
+    ok = mria:create_table(?SESSION_TRIE_DISC,
+                           [{rlog_shard, ?ROUTE_SHARD},
+                            {storage, disc_copies},
                             {record_name, ?TRIE},
                             {attributes, record_info(fields, ?TRIE)},
                             {type, ordered_set},
                             {storage_properties, StoreProps}]).
 
+
 %%--------------------------------------------------------------------
 %% Topics APIs
 %%--------------------------------------------------------------------
@@ -99,7 +114,7 @@ insert(Topic) when is_binary(Topic) ->
 
 -spec(insert_session(emqx_topic:topic()) -> ok).
 insert_session(Topic) when is_binary(Topic) ->
-    insert(Topic, ?SESSION_TRIE).
+    insert(Topic, ?ACTIVE_SESSION_TRIE).
 
 insert(Topic, Trie) when is_binary(Topic) ->
     {TopicKey, PrefixKeys} = make_keys(Topic),
@@ -116,7 +131,7 @@ delete(Topic) when is_binary(Topic) ->
 %% @doc Delete a topic filter from the trie.
 -spec(delete_session(emqx_topic:topic()) -> ok).
 delete_session(Topic) when is_binary(Topic) ->
-    delete(Topic, ?SESSION_TRIE).
+    delete(Topic, ?ACTIVE_SESSION_TRIE).
 
 delete(Topic, Trie) when is_binary(Topic) ->
     {TopicKey, PrefixKeys} = make_keys(Topic),
@@ -132,7 +147,7 @@ match(Topic) when is_binary(Topic) ->
 
 -spec(match_session(emqx_topic:topic()) -> list(emqx_topic:topic())).
 match_session(Topic) when is_binary(Topic) ->
-    match(Topic, ?SESSION_TRIE).
+    match(Topic, ?ACTIVE_SESSION_TRIE).
 
 match(Topic, Trie) when is_binary(Topic) ->
     Words = emqx_topic:words(Topic),
@@ -155,7 +170,7 @@ match(Topic, Trie) when is_binary(Topic) ->
 empty() -> empty(?TRIE).
 
 empty_session() ->
-    empty(?SESSION_TRIE).
+    empty(?ACTIVE_SESSION_TRIE).
 
 empty(Trie) -> ets:first(Trie) =:= '$end_of_table'.
 
@@ -165,7 +180,7 @@ lock_tables() ->
 
 -spec lock_session_tables() -> ok.
 lock_session_tables() ->
-    mnesia:write_lock_table(?SESSION_TRIE).
+    mnesia:write_lock_table(?ACTIVE_SESSION_TRIE).
 
 %%--------------------------------------------------------------------
 %% Internal functions

apps/emqx/test/emqx_persistent_session_SUITE.erl

@@ -124,15 +124,15 @@ init_per_group(gc_tests, Config) ->
                         receive stop -> ok end
                 end),
     meck:new(mnesia, [non_strict, passthrough, no_history, no_link]),
-    meck:expect(mnesia, dirty_first, fun(?SESS_MSG_TAB) -> ets:first(SessionMsgEts);
-                                        (?MSG_TAB) -> ets:first(MsgEts);
+    meck:expect(mnesia, dirty_first, fun(emqx_session_msg_ram) -> ets:first(SessionMsgEts);
+                                        (emqx_persistent_msg_ram) -> ets:first(MsgEts);
                                         (X) -> meck:passthrough(X)
                                      end),
-    meck:expect(mnesia, dirty_next, fun(?SESS_MSG_TAB, X) -> ets:next(SessionMsgEts, X);
-                                       (?MSG_TAB, X) -> ets:next(MsgEts, X);
+    meck:expect(mnesia, dirty_next, fun(emqx_session_msg_ram, X) -> ets:next(SessionMsgEts, X);
+                                       (emqx_persistent_msg_ram, X) -> ets:next(MsgEts, X);
                                        (Tab, X) -> meck:passthrough([Tab, X])
                                     end),
-    meck:expect(mnesia, dirty_delete, fun(?MSG_TAB, X) -> ets:delete(MsgEts, X);
+    meck:expect(mnesia, dirty_delete, fun(emqx_persistent_msg_ram, X) -> ets:delete(MsgEts, X);
                                          (Tab, X) -> meck:passthrough([Tab, X])
                                       end),
     [{store_owner, Pid}, {session_msg_store, SessionMsgEts}, {msg_store, MsgEts} | Config].