Replace match_object with dirty_match_object for binding cleanup.

match_object locks entire table, we'd like to avoid that.

It's possible to not call delete_for_source if exchange is autodeleted.
Checking an autodelete exchange will lock table on scanning for outgoing
bindings anyway. But other cases will not lock the table.

Author: hairyhum

src/rabbit_binding.erl

@@ -319,8 +319,8 @@ remove_for_source(SrcName) ->
     Match = #route{binding = #binding{source = SrcName, _ = '_'}},
     remove_routes(
       lists:usort(
-        mnesia:match_object(rabbit_route, Match, read) ++
-            mnesia:match_object(rabbit_semi_durable_route, Match, read))).
+        mnesia:dirty_match_object(rabbit_route, Match) ++
+            mnesia:dirty_match_object(rabbit_semi_durable_route, Match))).
 
 remove_for_destination(DstName, OnlyDurable) ->
     remove_for_destination(DstName, OnlyDurable, fun remove_routes/1).
@@ -443,13 +443,13 @@ remove_for_destination(DstName, OnlyDurable, Fun) ->
     Routes = case OnlyDurable of
                  false ->
                         [reverse_route(R) ||
-                              R <- mnesia:match_object(
-                                     rabbit_reverse_route, MatchRev, read)];
+                              R <- mnesia:dirty_match_object(
+                                     rabbit_reverse_route, MatchRev)];
                  true  -> lists:usort(
-                            mnesia:match_object(
-                              rabbit_durable_route, MatchFwd, read) ++
-                                mnesia:match_object(
-                                  rabbit_semi_durable_route, MatchFwd, read))
+                            mnesia:dirty_match_object(
+                              rabbit_durable_route, MatchFwd) ++
+                                mnesia:dirty_match_object(
+                                  rabbit_semi_durable_route, MatchFwd))
              end,
     Bindings = Fun(Routes),
     group_bindings_fold(fun maybe_auto_delete/4, new_deletions(),

src/rabbit_exchange.erl

@@ -492,15 +492,21 @@ maybe_auto_delete(#exchange{auto_delete = true} = X, OnlyDurable) ->
 
 conditional_delete(X = #exchange{name = XName}, OnlyDurable) ->
     case rabbit_binding:has_for_source(XName) of
-        false  -> unconditional_delete(X, OnlyDurable);
+        false  -> internal_delete(X, OnlyDurable, false);
         true   -> {error, in_use}
     end.
 
-unconditional_delete(X = #exchange{name = XName}, OnlyDurable) ->
+unconditional_delete(X, OnlyDurable) ->
+    internal_delete(X, OnlyDurable, true).
+
+internal_delete(X = #exchange{name = XName}, OnlyDurable, RemoveBindingsForSource) ->
     ok = mnesia:delete({rabbit_exchange, XName}),
     ok = mnesia:delete({rabbit_exchange_serial, XName}),
     mnesia:delete({rabbit_durable_exchange, XName}),
-    Bindings = rabbit_binding:remove_for_source(XName),
+    Bindings = case RemoveBindingsForSource of
+        true  -> rabbit_binding:remove_for_source(XName);
+        false -> []
+    end,
     {deleted, X, Bindings, rabbit_binding:remove_for_destination(
                              XName, OnlyDurable)}.