Use new OTP 26 fun ets:lookup_element/4

Routing to nowhere with the direct exchange is now a bit faster:
```
java -jar target/perf-test.jar -x 2 -y 0 -k route-nowhere -z 60
```

Remove dead code rabbit_db_binding:route_v2/3

Author: ansd

deps/rabbit/src/rabbit_db_binding.erl

@@ -20,7 +20,7 @@
          fold/2]).
 
 %% Routing. These functions are in the hot code path
--export([match/2, match_routing_key/3]).
+-export([match/2, match_routing_key/2]).
 
 %% Exported to be used by various rabbit_db_* modules
 -export([
@@ -398,31 +398,22 @@ match_in_mnesia(SrcName, Match) ->
 %% match_routing_key().
 %% -------------------------------------------------------------------
 
--spec match_routing_key(Src, RoutingKeys, UseIndex) -> [Dst] when
+-spec match_routing_key(Src, RoutingKeys) -> [Dst] when
       Src :: rabbit_types:binding_source(),
       Dst :: rabbit_types:binding_destination(),
-      RoutingKeys :: [binary() | '_'],
-      UseIndex :: boolean().
+      RoutingKeys :: [binary() | '_'].
 %% @doc Matches all binding records that have `Src' as source of the binding
 %% and that match any routing key in `RoutingKeys'.
 %%
 %% @returns the list of destinations
 %%
 %% @private
 
-match_routing_key(SrcName, RoutingKeys, UseIndex) ->
+match_routing_key(SrcName, RoutingKeys) ->
     rabbit_db:run(
-      #{mnesia => fun() -> match_routing_key_in_mnesia(SrcName, RoutingKeys, UseIndex) end
+      #{mnesia => fun() -> route_in_mnesia(SrcName, RoutingKeys) end
        }).
 
-match_routing_key_in_mnesia(SrcName, RoutingKeys, UseIndex) ->
-    case UseIndex of
-        true ->
-            route_v2(?MNESIA_INDEX_TABLE, SrcName, RoutingKeys);
-        _ ->
-            route_in_mnesia_v1(SrcName, RoutingKeys)
-    end.
-
 %% -------------------------------------------------------------------
 %% recover().
 %% -------------------------------------------------------------------
@@ -728,13 +719,13 @@ continue({[], Continuation}) -> continue(mnesia:select(Continuation)).
 
 %% Routing. Hot code path
 %% -------------------------------------------------------------------------
-route_in_mnesia_v1(SrcName, [RoutingKey]) ->
+route_in_mnesia(SrcName, [RoutingKey]) ->
     MatchHead = #route{binding = #binding{source      = SrcName,
                                           destination = '$1',
                                           key         = RoutingKey,
                                           _           = '_'}},
     ets:select(?MNESIA_TABLE, [{MatchHead, [], ['$1']}]);
-route_in_mnesia_v1(SrcName, [_|_] = RoutingKeys) ->
+route_in_mnesia(SrcName, [_|_] = RoutingKeys) ->
     %% Normally we'd call mnesia:dirty_select/2 here, but that is quite
     %% expensive for the same reasons as above, and, additionally, due to
     %% mnesia 'fixing' the table with ets:safe_fixtable/2, which is wholly
@@ -753,36 +744,3 @@ route_in_mnesia_v1(SrcName, [_|_] = RoutingKeys) ->
     Conditions = [list_to_tuple(['orelse' | [{'=:=', '$2', RKey} ||
                                                 RKey <- RoutingKeys]])],
     ets:select(?MNESIA_TABLE, [{MatchHead, Conditions, ['$1']}]).
-
-%% rabbit_router:match_routing_key/2 uses ets:select/2 to get destinations.
-%% ets:select/2 is expensive because it needs to compile the match spec every
-%% time and lookup does not happen by a hash key.
-%%
-%% In contrast, route_v2/2 increases end-to-end message sending throughput
-%% (i.e. from RabbitMQ client to the queue process) by up to 35% by using ets:lookup_element/3.
-%% Only the direct exchange type uses the rabbit_index_route table to store its
-%% bindings by table key tuple {SourceExchange, RoutingKey}.
--spec route_v2(ets:table(), rabbit_types:binding_source(), [rabbit_router:routing_key(), ...]) ->
-    rabbit_router:match_result().
-route_v2(Table, SrcName, [RoutingKey]) ->
-    %% optimization
-    destinations(Table, SrcName, RoutingKey);
-route_v2(Table, SrcName, [_|_] = RoutingKeys) ->
-    lists:flatmap(fun(Key) ->
-                          destinations(Table, SrcName, Key)
-                  end, RoutingKeys).
-
-destinations(Table, SrcName, RoutingKey) ->
-    %% Prefer try-catch block over checking Key existence with ets:member/2.
-    %% The latter reduces throughput by a few thousand messages per second because
-    %% of function db_member_hash in file erl_db_hash.c.
-    %% We optimise for the happy path, that is the binding / table key is present.
-    try
-        ets:lookup_element(Table,
-                           {SrcName, RoutingKey},
-                           #index_route.destination)
-    catch
-        error:badarg ->
-            []
-    end.
-

deps/rabbit/src/rabbit_exchange_type_direct.erl

@@ -53,7 +53,7 @@ assert_args_equivalence(X, Args) ->
 %% time and lookup does not happen by a hash key.
 %%
 %% In contrast, route_v2/2 increases end-to-end message sending throughput
-%% (i.e. from RabbitMQ client to the queue process) by up to 35% by using ets:lookup_element/3.
+%% (i.e. from RabbitMQ client to the queue process) by up to 35% by using ets:lookup_element/4.
 %% Only the direct exchange type uses the rabbit_index_route table to store its
 %% bindings by table key tuple {SourceExchange, RoutingKey}.
 -spec route_v2(rabbit_types:binding_source(), [rabbit_router:routing_key(), ...]) ->
@@ -67,15 +67,7 @@ route_v2(SrcName, [_|_] = RoutingKeys) ->
                   end, RoutingKeys).
 
 destinations(SrcName, RoutingKey) ->
-    %% Prefer try-catch block over checking Key existence with ets:member/2.
-    %% The latter reduces throughput by a few thousand messages per second because
-    %% of function db_member_hash in file erl_db_hash.c.
-    %% We optimise for the happy path, that is the binding / table key is present.
-    try
-        ets:lookup_element(rabbit_index_route,
-                           {SrcName, RoutingKey},
-                           #index_route.destination)
-    catch
-        error:badarg ->
-            []
-    end.
+    ets:lookup_element(rabbit_index_route,
+                       {SrcName, RoutingKey},
+                       #index_route.destination,
+                       []).

deps/rabbit/src/rabbit_quorum_queue.erl

@@ -1000,7 +1000,7 @@ cluster_state(Name) ->
     case whereis(Name) of
         undefined -> down;
         _ ->
-            case ets_lookup_element(ra_state, Name, 2, undefined) of
+            case ets:lookup_element(ra_state, Name, 2, undefined) of
                 recover ->
                     recovering;
                 _ ->
@@ -1397,10 +1397,10 @@ i(messages, Q) when ?is_amqqueue(Q) ->
     quorum_messages(QName);
 i(messages_ready, Q) when ?is_amqqueue(Q) ->
     QName = amqqueue:get_name(Q),
-    ets_lookup_element(queue_coarse_metrics, QName, 2, 0);
+    ets:lookup_element(queue_coarse_metrics, QName, 2, 0);
 i(messages_unacknowledged, Q) when ?is_amqqueue(Q) ->
     QName = amqqueue:get_name(Q),
-    ets_lookup_element(queue_coarse_metrics, QName, 3, 0);
+    ets:lookup_element(queue_coarse_metrics, QName, 3, 0);
 i(policy, Q) ->
     case rabbit_policy:name(Q) of
         none   -> '';
@@ -1418,7 +1418,7 @@ i(effective_policy_definition, Q) ->
     end;
 i(consumers, Q) when ?is_amqqueue(Q) ->
     QName = amqqueue:get_name(Q),
-    Consumers = ets_lookup_element(queue_metrics, QName, 2, []),
+    Consumers = ets:lookup_element(queue_metrics, QName, 2, []),
     proplists:get_value(consumers, Consumers, 0);
 i(memory, Q) when ?is_amqqueue(Q) ->
     {Name, _} = amqqueue:get_pid(Q),
@@ -1440,7 +1440,7 @@ i(state, Q) when ?is_amqqueue(Q) ->
     end;
 i(local_state, Q) when ?is_amqqueue(Q) ->
     {Name, _} = amqqueue:get_pid(Q),
-    ets_lookup_element(ra_state, Name, 2, not_member);
+    ets:lookup_element(ra_state, Name, 2, not_member);
 i(garbage_collection, Q) when ?is_amqqueue(Q) ->
     {Name, _} = amqqueue:get_pid(Q),
     try
@@ -1517,7 +1517,7 @@ open_files(Name) ->
         undefined ->
             {node(), 0};
         Pid ->
-            {node(), ets_lookup_element(ra_open_file_metrics, Pid, 2, 0)}
+            {node(), ets:lookup_element(ra_open_file_metrics, Pid, 2, 0)}
     end.
 
 leader(Q) when ?is_amqqueue(Q) ->
@@ -1576,7 +1576,7 @@ is_process_alive(Name, Node) ->
 -spec quorum_messages(rabbit_amqqueue:name()) -> non_neg_integer().
 
 quorum_messages(QName) ->
-    ets_lookup_element(queue_coarse_metrics, QName, 4, 0).
+    ets:lookup_element(queue_coarse_metrics, QName, 4, 0).
 
 quorum_ctag(Int) when is_integer(Int) ->
     integer_to_binary(Int);
@@ -1695,14 +1695,6 @@ prepare_content(Content) ->
     %% rabbit_fifo can directly parse it without having to decode again.
     Content.
 
-ets_lookup_element(Tbl, Key, Pos, Default) ->
-    try ets:lookup_element(Tbl, Key, Pos) of
-        V -> V
-    catch
-        _:badarg ->
-            Default
-    end.
-
 erpc_call(Node, M, F, A, _Timeout)
   when Node =:= node()  ->
     %% Only timeout 'infinity' optimises the local call in OTP 23-25 avoiding a new process being spawned:

deps/rabbit/src/rabbit_router.erl

@@ -32,4 +32,4 @@ match_bindings(SrcName, Match) ->
     match_result().
 
 match_routing_key(SrcName, RoutingKeys) ->
-    rabbit_db_binding:match_routing_key(SrcName, RoutingKeys, false).
+    rabbit_db_binding:match_routing_key(SrcName, RoutingKeys).

deps/rabbit/test/rabbit_db_binding_SUITE.erl

@@ -322,10 +322,10 @@ match_routing_key1(_Config) ->
     Exchange2 = #exchange{name = XName2, durable = true},
     Binding = #binding{source = XName1, key = <<"*.*">>, destination = XName2,
                        args = #{foo => bar}},
-    ?assertEqual([], rabbit_db_binding:match_routing_key(XName1, [<<"a.b.c">>], false)),
+    ?assertEqual([], rabbit_db_binding:match_routing_key(XName1, [<<"a.b.c">>])),
     ?assertMatch({new, #exchange{}}, rabbit_db_exchange:create_or_get(Exchange1)),
     ?assertMatch({new, #exchange{}}, rabbit_db_exchange:create_or_get(Exchange2)),
     ?assertMatch(ok, rabbit_db_binding:create(Binding, fun(_, _) -> ok end)),
-    ?assertEqual([], rabbit_db_binding:match_routing_key(XName1, [<<"a.b.c">>], false)),
-    ?assertEqual([XName2], rabbit_db_binding:match_routing_key(XName1, [<<"a.b">>], false)),
+    ?assertEqual([], rabbit_db_binding:match_routing_key(XName1, [<<"a.b.c">>])),
+    ?assertEqual([XName2], rabbit_db_binding:match_routing_key(XName1, [<<"a.b">>])),
     passed.

deps/rabbitmq_management_agent/src/rabbit_mgmt_data.erl

@@ -367,12 +367,11 @@ match_consumer_spec(Id) ->
 match_queue_consumer_spec(Id) ->
     [{{{'$1', '_', '_'}, '_'}, [{'==', {Id}, '$1'}], ['$_']}].
 
-lookup_element(Table, Key) -> lookup_element(Table, Key, 2).
+lookup_element(Table, Key) ->
+    lookup_element(Table, Key, 2).
 
 lookup_element(Table, Key, Pos) ->
-    try ets:lookup_element(Table, Key, Pos)
-    catch error:badarg -> []
-    end.
+    ets:lookup_element(Table, Key, Pos, []).
 
 -spec lookup_smaller_sample(atom(), any()) -> maybe_slide().
 lookup_smaller_sample(Table, Id) ->