Faster implementation of rabbit_binding:recover/0

For a large number of bindings, this implementation reduces the recovery
time from minutes to seconds. rabbit_binding:recover/2 is the second
operation that may take minutes but it can be improved separately.

deps/rabbit/src/rabbit_binding.erl

@@ -77,15 +77,16 @@ new(Src, RoutingKey, Dst, Arguments) ->
 %% Global table recovery
 
 recover() ->
-    rabbit_misc:table_filter(
-        fun (Route) ->
-            mnesia:read({rabbit_semi_durable_route, Route}) =:= []
-        end,
-        fun (Route,  true) ->
-            ok = mnesia:write(rabbit_semi_durable_route, Route, write);
-            (_Route, false) ->
-                ok
-        end, rabbit_durable_route).
+    rabbit_misc:execute_mnesia_transaction(
+        fun () ->
+            mnesia:lock({table, rabbit_durable_route}, read),
+            mnesia:lock({table, rabbit_semi_durable_route}, write),
+            Routes = rabbit_misc:dirty_read_all(rabbit_durable_route),
+            Fun = fun(Route) ->
+                mnesia:dirty_write(rabbit_semi_durable_route, Route)
+            end,
+        lists:foreach(Fun, Routes)
+    end).
 
 %% Virtual host-specific recovery
 

deps/rabbit/src/rabbit_vhost.erl

@@ -37,7 +37,10 @@ recover() ->
     rabbit_amqqueue:warn_file_limit(),
 
     %% Prepare rabbit_semi_durable_route table
-    rabbit_binding:recover(),
+    {Time, _} = timer:tc(fun() ->
+                                 rabbit_binding:recover()
+                         end),
+    rabbit_log:debug("rabbit_binding:recover/0 completed in ~fs", [Time/1000000]),
 
     %% rabbit_vhost_sup_sup will start the actual recovery.
     %% So recovery will be run every time a vhost supervisor is restarted.
@@ -57,7 +60,11 @@ recover(VHost) ->
     {Recovered, Failed} = rabbit_amqqueue:recover(VHost),
     AllQs = Recovered ++ Failed,
     QNames = [amqqueue:get_name(Q) || Q <- AllQs],
-    ok = rabbit_binding:recover(rabbit_exchange:recover(VHost), QNames),
+    {Time, ok} = timer:tc(fun() ->
+                                  rabbit_binding:recover(rabbit_exchange:recover(VHost), QNames)
+                          end),
+    rabbit_log:debug("rabbit_binding:recover/2 for vhost ~s completed in ~fs", [VHost, Time/1000000]),
+
     ok = rabbit_amqqueue:start(Recovered),
     %% Start queue mirrors.
     ok = rabbit_mirror_queue_misc:on_vhost_up(VHost),