how_to_reproduce_ets_bug.erl

-module(test).

-export([start/2, stop/1]).
-export([loop/2, loop_child/1]).

-define(NUM_OF_REC,      256).
-define(INTERVAL,         1).

%% public functions
start(ProcNum, _Table) when ProcNum < 1 ->
    {error, badarg};
start(ProcNum, Table) ->
    _ = ets:new(Table, [named_table, ordered_set, public, {read_concurrency, true}]),
    load_ets(?NUM_OF_REC, Table),
    spawn(?MODULE, loop, [ProcNum, Table]).

stop(Pid) ->
    Pid ! {stop, self()}.

%% private functions
load_ets(0, _Table) ->
    ok;
load_ets(Id, Table) ->
    true = ets:insert(Table, {Id, node()}),
    load_ets(Id - 1, Table).

loop(ProcNum, Table) ->
    loop(ProcNum, Table, []).
loop(0, Table, Acc) ->
    receive
        {stop, Pid}->
            [ChildPid ! stop || ChildPid <- Acc],
            Pid ! ok;
        Other ->
            io:format("[err] received unknown msg:~p table:~p ~n", [Other, Table]),
            loop(0, Table, Acc)
    end;
loop(ProcNum, Table, Acc) ->
    Pid = spawn(?MODULE, loop_child, [Table]),
    loop(ProcNum - 1, Table, [Pid|Acc]).

loop_child(Table) ->
    receive
        stop ->
            io:format("[info] received stop msg ~n"),
            exit(stop);
        Other ->
            io:format("[err] received unknown msg:~p ~n", [Other]),
            loop_child(Table)
    after
        ?INTERVAL ->
            void
    end,
    case ets:foldl(
                 fun({_, Member}, Acc) ->
                         ordsets:add_element(Member, Acc)
                 end, [], Table) of
        [] ->
            io:format("[err] succeeded reproducing the bug ets info:~p i:~p ~n",
                      [ets:info(Table), ets:i()]);
        _Members ->
            %% always must be reached here
            loop_child(Table)
    end.

In progress

Under high load situations, Occasionary
https://github.com/leo-project/leo_redundant_manager/blob/0.14.3/src/leo_redundant_manager_api.erl#L392 's error occured, This is because failing ets:foldl/3.
So I started to survey how to reproduce this bug in less code...