fix(emqx_trace): Read the data locally

apps/emqx/src/emqx_trace/emqx_trace.erl

@@ -21,9 +21,6 @@
 -include_lib("emqx/include/logger.hrl").
 -include_lib("snabbkaffe/include/trace.hrl").
 
--boot_mnesia({mnesia, [boot]}).
--export([mnesia/1]).
-
 -export([
     publish/1,
     subscribe/3,
@@ -55,6 +52,7 @@
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3]).
 
 -define(TRACE, ?MODULE).
+-define(SHARD, ?COMMON_SHARD).
 -define(MAX_SIZE, 30).
 -define(OWN_KEYS, [level, filters, filter_default, handlers]).
 
@@ -77,15 +75,6 @@
     end_at :: integer() | undefined | '_'
 }).
 
-mnesia(boot) ->
-    ok = mria:create_table(?TRACE, [
-        {type, set},
-        {rlog_shard, ?COMMON_SHARD},
-        {storage, disc_copies},
-        {record_name, ?TRACE},
-        {attributes, record_info(fields, ?TRACE)}
-    ]).
-
 publish(#message{topic = <<"$SYS/", _/binary>>}) ->
     ignore;
 publish(#message{from = From, topic = Topic, payload = Payload}) when
@@ -255,12 +244,19 @@ format(Traces) ->
     ).
 
 init([]) ->
-    ok = mria:wait_for_tables([?TRACE]),
     erlang:process_flag(trap_exit, true),
+    ok = mria:create_table(?TRACE, [
+        {type, set},
+        {rlog_shard, ?SHARD},
+        {storage, disc_copies},
+        {record_name, ?TRACE},
+        {attributes, record_info(fields, ?TRACE)}
+    ]),
+    ok = mria:wait_for_tables([?TRACE]),
+    {ok, _} = mnesia:subscribe({table, ?TRACE, simple}),
     ok = filelib:ensure_dir(filename:join([trace_dir(), dummy])),
     ok = filelib:ensure_dir(filename:join([zip_dir(), dummy])),
-    {ok, _} = mnesia:subscribe({table, ?TRACE, simple}),
-    Traces = get_enable_trace(),
+    Traces = get_enabled_trace(),
     TRef = update_trace(Traces),
     update_trace_handler(),
     {ok, #{timer => TRef, monitors => #{}}}.
@@ -288,7 +284,7 @@ handle_info({'DOWN', _Ref, process, Pid, _Reason}, State = #{monitors := Monitor
             {noreply, State#{monitors => NewMonitors}}
     end;
 handle_info({timeout, TRef, update_trace}, #{timer := TRef} = State) ->
-    Traces = get_enable_trace(),
+    Traces = get_enabled_trace(),
     NextTRef = update_trace(Traces),
     update_trace_handler(),
     ?tp(update_trace_done, #{}),
@@ -347,10 +343,13 @@ stop_all_trace_handler() ->
         fun(#{id := Id}) -> emqx_trace_handler:uninstall(Id) end,
         emqx_trace_handler:running()
     ).
-get_enable_trace() ->
-    transaction(fun() ->
-        mnesia:match_object(?TRACE, #?TRACE{enable = true, _ = '_'}, read)
-    end).
+
+get_enabled_trace() ->
+    {atomic, Traces} =
+        mria:ro_transaction(?SHARD, fun() ->
+            mnesia:match_object(?TRACE, #?TRACE{enable = true, _ = '_'}, read)
+        end),
+    Traces.
 
 find_closest_time(Traces, Now) ->
     Sec =