diff --git a/apps/emqx_durable_storage/src/emqx_ds.erl b/apps/emqx_durable_storage/src/emqx_ds.erl
index b1a003e93..941573bf8 100644
--- a/apps/emqx_durable_storage/src/emqx_ds.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds.erl
@@ -43,6 +43,7 @@
     stream/0,
     stream_rank/0,
     iterator/0,
+    message_id/0,
     next_result/1, next_result/0,
     store_batch_result/0,
     make_iterator_result/1, make_iterator_result/0
diff --git a/apps/emqx_durable_storage/src/emqx_ds_bitmask_keymapper.erl b/apps/emqx_durable_storage/src/emqx_ds_bitmask_keymapper.erl
index a512a141c..e18c8498d 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_bitmask_keymapper.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_bitmask_keymapper.erl
@@ -105,6 +105,8 @@
     ]}
 ).
 
+-elvis([{elvis_style, no_if_expression, disable}]).
+
 -ifdef(TEST).
 -include_lib("proper/include/proper.hrl").
 -include_lib("eunit/include/eunit.hrl").
@@ -139,7 +141,9 @@
     dst_offset :: offset()
 }).
 
--type scanner() :: [[#scan_action{}]].
+-type scan_action() :: #scan_action{}.
+
+-type scanner() :: [[scan_action()]].
 
 -record(keymapper, {
     schema :: [bitsource()],
@@ -259,7 +263,9 @@ key_to_bitstring(#keymapper{size = Size}, Key) ->
 
 %% @doc Create a filter object that facilitates range scans.
 -spec make_filter(keymapper(), [scalar_range()]) -> filter().
-make_filter(KeyMapper = #keymapper{schema = Schema, dim_sizeof = DimSizeof, size = Size}, Filter0) ->
+make_filter(
+    KeyMapper = #keymapper{schema = Schema, dim_sizeof = DimSizeof, size = TotalSize}, Filter0
+) ->
     NDim = length(DimSizeof),
     %% Transform "symbolic" inequations to ranges:
     Filter1 = inequations_to_ranges(KeyMapper, Filter0),
@@ -326,7 +332,7 @@ make_filter(KeyMapper = #keymapper{schema = Schema, dim_sizeof = DimSizeof, size
     end,
     %% Final value
     #filter{
-        size = Size,
+        size = TotalSize,
         bitmask = Bitmask,
         bitfilter = Bitfilter,
         bitsource_ranges = Ranges,
@@ -420,7 +426,7 @@ ratchet_scan(Ranges, NDim, Key, I, Pivot0, Carry) ->
 %% Note: this function operates in bitsource basis, scanning it from
 %% NDim to 0. It applies the transformation specified by
 %% `ratchet_scan'.
-ratchet_do(Ranges, Key, I, _Pivot, _Increment) when I < 0 ->
+ratchet_do(_Ranges, _Key, I, _Pivot, _Increment) when I < 0 ->
     0;
 ratchet_do(Ranges, Key, I, Pivot, Increment) ->
     #filter_scan_action{offset = Offset, size = Size, min = Min} = array:get(I, Ranges),
@@ -495,12 +501,12 @@ do_vector_to_key([Action | Actions], Scanner, Coord, Vector, Acc0) ->
     Acc = Acc0 bor extract(Coord, Action),
     do_vector_to_key(Actions, Scanner, Coord, Vector, Acc).
 
--spec extract(_Source :: scalar(), #scan_action{}) -> integer().
+-spec extract(_Source :: scalar(), scan_action()) -> integer().
 extract(Src, #scan_action{src_bitmask = SrcBitmask, src_offset = SrcOffset, dst_offset = DstOffset}) ->
     ((Src bsr SrcOffset) band SrcBitmask) bsl DstOffset.
 
 %% extract^-1
--spec extract_inv(_Dest :: scalar(), #scan_action{}) -> integer().
+-spec extract_inv(_Dest :: scalar(), scan_action()) -> integer().
 extract_inv(Dest, #scan_action{
     src_bitmask = SrcBitmask, src_offset = SrcOffset, dst_offset = DestOffset
 }) ->
diff --git a/apps/emqx_durable_storage/src/emqx_ds_lts.erl b/apps/emqx_durable_storage/src/emqx_ds_lts.erl
index c9a73e3e0..d06854fd0 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_lts.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_lts.erl
@@ -32,6 +32,8 @@
 -include_lib("eunit/include/eunit.hrl").
 -endif.
 
+-elvis([{elvis_style, variable_naming_convention, disable}]).
+
 %%================================================================================
 %% Type declarations
 %%================================================================================
@@ -601,7 +603,11 @@ test_key(Trie, Threshold, Topic0) ->
                 fun(Old) ->
                         case Old =:= Topic of
                             true  -> Old;
-                            false -> error(#{'$msg' => "Duplicate key!", key => Ret, old_topic => Old, new_topic => Topic})
+                            false -> error(#{ '$msg' => "Duplicate key!"
+                                            , key => Ret
+                                            , old_topic => Old
+                                            , new_topic => Topic
+                                            })
                         end
                 end,
                 Topic,
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
index 8d406c93e..b85fb48b0 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_bitfield_lts.erl
@@ -21,7 +21,7 @@
 %% used for testing.
 -module(emqx_ds_storage_bitfield_lts).
 
--behavior(emqx_ds_storage_layer).
+-behaviour(emqx_ds_storage_layer).
 
 %% API:
 -export([]).
@@ -65,6 +65,8 @@
     keymappers :: array:array(emqx_ds_bitmask_keymapper:keymapper())
 }).
 
+-type s() :: #s{}.
+
 -record(stream, {
     storage_key :: emqx_ds_lts:msg_storage_key()
 }).
@@ -76,9 +78,7 @@
     last_seen_key = <<>> :: binary()
 }).
 
--define(QUICKCHECK_KEY(KEY, BITMASK, BITFILTER),
-    ((KEY band BITMASK) =:= BITFILTER)
-).
+-type iterator() :: #it{}.
 
 -define(COUNTER, emqx_ds_storage_bitfield_lts_counter).
 
@@ -92,6 +92,13 @@
 %% behavior callbacks
 %%================================================================================
 
+-spec create(
+    emqx_ds_replication_layer:shard_id(),
+    rocksdb:db_handle(),
+    emqx_ds_storage_layer:gen_id(),
+    options()
+) ->
+    {schema(), emqx_ds_storage_layer:cf_refs()}.
 create(_ShardId, DBHandle, GenId, Options) ->
     %% Get options:
     BitsPerTopicLevel = maps:get(bits_per_wildcard_level, Options, 64),
@@ -112,6 +119,14 @@ create(_ShardId, DBHandle, GenId, Options) ->
     },
     {Schema, [{DataCFName, DataCFHandle}, {TrieCFName, TrieCFHandle}]}.
 
+-spec open(
+    emqx_ds_replication_layer:shard_id(),
+    rocksdb:db_handle(),
+    emqx_ds_storage_layer:gen_id(),
+    emqx_ds_storage_layer:cf_refs(),
+    schema()
+) ->
+    s().
 open(_Shard, DBHandle, GenId, CFRefs, Schema) ->
     #{
         bits_per_wildcard_level := BitsPerTopicLevel,
@@ -134,6 +149,10 @@ open(_Shard, DBHandle, GenId, CFRefs, Schema) ->
     ),
     #s{db = DBHandle, data = DataCF, trie = Trie, keymappers = KeymapperCache}.
 
+-spec store_batch(
+    emqx_ds_replication_layer:shard_id(), s(), [emqx_types:message()], emqx_ds:message_store_opts()
+) ->
+    emqx_ds:store_batch_result().
 store_batch(_ShardId, S = #s{db = DB, data = Data}, Messages, _Options) ->
     lists:foreach(
         fun(Msg) ->
@@ -203,7 +222,7 @@ next(_Shard, #s{db = DB, data = CF, keymappers = Keymappers}, It0, BatchSize) ->
 %% Internal functions
 %%================================================================================
 
-next_loop(ITHandle, KeyMapper, Filter, It, Acc, 0) ->
+next_loop(_ITHandle, _KeyMapper, _Filter, It, Acc, 0) ->
     {ok, It, lists:reverse(Acc)};
 next_loop(ITHandle, KeyMapper, Filter, It0, Acc0, N0) ->
     inc_counter(),
@@ -249,8 +268,8 @@ traverse_interval(ITHandle, KeyMapper, Filter, It0, Acc, N) ->
             {0, It0, Acc}
     end.
 
--spec check_message(emqx_ds_bitmask_keymapper:filter(), #it{}, binary()) ->
-    {true, #message{}} | false.
+-spec check_message(emqx_ds_bitmask_keymapper:filter(), iterator(), binary()) ->
+    {true, emqx_types:message()} | false.
 check_message(Filter, #it{last_seen_key = Key}, Val) ->
     case emqx_ds_bitmask_keymapper:bin_checkmask(Filter, Key) of
         true ->
@@ -270,7 +289,7 @@ format_keyfilter(any) ->
 format_keyfilter({Op, Val}) ->
     {Op, integer_to_list(Val, 16)}.
 
--spec make_key(#s{}, #message{}) -> {binary(), [binary()]}.
+-spec make_key(s(), emqx_types:message()) -> {binary(), [binary()]}.
 make_key(#s{keymappers = KeyMappers, trie = Trie}, #message{timestamp = Timestamp, topic = TopicBin}) ->
     Tokens = emqx_topic:tokens(TopicBin),
     {TopicIndex, Varying} = emqx_ds_lts:topic_key(Trie, fun threshold_fun/1, Tokens),
@@ -345,7 +364,7 @@ read_persisted_trie(IT, {ok, KeyB, ValB}) ->
         {binary_to_term(KeyB), binary_to_term(ValB)}
         | read_persisted_trie(IT, rocksdb:iterator_move(IT, next))
     ];
-read_persisted_trie(IT, {error, invalid_iterator}) ->
+read_persisted_trie(_IT, {error, invalid_iterator}) ->
     [].
 
 inc_counter() ->
diff --git a/apps/emqx_durable_storage/src/emqx_ds_storage_reference.erl b/apps/emqx_durable_storage/src/emqx_ds_storage_reference.erl
index 9c7fc3158..ec00f1310 100644
--- a/apps/emqx_durable_storage/src/emqx_ds_storage_reference.erl
+++ b/apps/emqx_durable_storage/src/emqx_ds_storage_reference.erl
@@ -21,7 +21,7 @@
 %% used for testing.
 -module(emqx_ds_storage_reference).
 
--behavior(emqx_ds_storage_layer).
+-behaviour(emqx_ds_storage_layer).
 
 %% API:
 -export([]).
diff --git a/apps/emqx_durable_storage/test/emqx_ds_storage_bitfield_lts_SUITE.erl b/apps/emqx_durable_storage/test/emqx_ds_storage_bitfield_lts_SUITE.erl
index ac037e861..6dc24a269 100644
--- a/apps/emqx_durable_storage/test/emqx_ds_storage_bitfield_lts_SUITE.erl
+++ b/apps/emqx_durable_storage/test/emqx_ds_storage_bitfield_lts_SUITE.erl
@@ -354,36 +354,6 @@ store(Shard, PublishedAt, Topic, Payload) ->
     },
     emqx_ds_storage_layer:message_store(Shard, [Msg], #{}).
 
-%% iterate(Shard, TopicFilter, StartTime) ->
-%%     Streams = emqx_ds_storage_layer:get_streams(Shard, TopicFilter, StartTime),
-%%     lists:flatmap(
-%%       fun(Stream) ->
-%%               iterate(Shard, iterator(Shard, Stream, TopicFilter, StartTime))
-%%       end,
-%%       Streams).
-
-%% iterate(Shard, It) ->
-%%     case emqx_ds_storage_layer:next(Shard, It) of
-%%         {ok, ItNext, [#message{payload = Payload}]} ->
-%%             [Payload | iterate(Shard, ItNext)];
-%%         end_of_stream ->
-%%             []
-%%     end.
-
-%% iterate(_Shard, end_of_stream, _N) ->
-%%     {end_of_stream, []};
-%% iterate(Shard, It, N) ->
-%%     case emqx_ds_storage_layer:next(Shard, It, N) of
-%%         {ok, ItFinal, Messages} ->
-%%             {ItFinal, [Payload || #message{payload = Payload} <- Messages]};
-%%         end_of_stream ->
-%%             {end_of_stream, []}
-%%     end.
-
-%% iterator(Shard, Stream, TopicFilter, StartTime) ->
-%%     {ok, It} = emqx_ds_storage_layer:make_iterator(Shard, Stream, parse_topic(TopicFilter), StartTime),
-%%     It.
-
 payloads(Messages) ->
     lists:map(
         fun(#message{payload = P}) ->