merge bug20500 into v1_5

Author: Matthew Sackman

src/rabbit_amqqueue.erl

@@ -122,19 +122,32 @@ recover() ->
 
 recover_durable_queues() ->
     Node = node(),
-    %% TODO: use dirty ops instead
-    R = rabbit_misc:execute_mnesia_transaction(
-          fun () ->
-                  qlc:e(qlc:q([Q || Q = #amqqueue{pid = Pid}
-                                        <- mnesia:table(durable_queues),
-                                    node(Pid) == Node]))
-          end),
-    Queues = lists:map(fun start_queue_process/1, R),
-    rabbit_misc:execute_mnesia_transaction(
-      fun () ->
-              lists:foreach(fun store_queue/1, Queues),
-              ok
-      end).
+    lists:foreach(
+      fun (RecoveredQ) ->
+              Q = start_queue_process(RecoveredQ),
+              %% We need to catch the case where a client connected to
+              %% another node has deleted the queue (and possibly
+              %% re-created it).
+              case rabbit_misc:execute_mnesia_transaction(
+                     fun () -> case mnesia:match_object(
+                                 durable_queues, RecoveredQ, read) of
+                                   [_] -> ok = store_queue(Q),
+                                          true;
+                                   []  -> false
+                               end
+                     end) of
+                  true  -> ok;
+                  false -> exit(Q#amqqueue.pid, shutdown)
+              end
+      end,
+      %% TODO: use dirty ops instead
+      rabbit_misc:execute_mnesia_transaction(
+        fun () ->
+                qlc:e(qlc:q([Q || Q = #amqqueue{pid = Pid}
+                                      <- mnesia:table(durable_queues),
+                                  node(Pid) == Node]))
+        end)),
+    ok.
 
 declare(QueueName, Durable, AutoDelete, Args) ->
     Q = start_queue_process(#amqqueue{name = QueueName,

src/rabbit_exchange.erl

@@ -102,22 +102,15 @@
 -define(INFO_KEYS, [name, type, durable, auto_delete, arguments].
 
 recover() ->
-    rabbit_misc:execute_mnesia_transaction(
-      fun () ->
-              mnesia:foldl(
-                fun (Exchange, Acc) ->
-                        ok = mnesia:write(Exchange),
-                        Acc
-                end, ok, durable_exchanges),
-              mnesia:foldl(
-                fun (Route, Acc) ->
-                        {_, ReverseRoute} = route_with_reverse(Route),
-                        ok = mnesia:write(Route),
-                        ok = mnesia:write(ReverseRoute),
-                        Acc
-                end, ok, durable_routes),
-              ok
-      end).
+    ok = rabbit_misc:table_foreach(
+           fun(Exchange) -> ok = mnesia:write(Exchange) end,
+           durable_exchanges),
+    ok = rabbit_misc:table_foreach(
+           fun(Route) -> {_, ReverseRoute} = route_with_reverse(Route),
+                         ok = mnesia:write(Route),
+                         ok = mnesia:write(ReverseRoute)
+           end, durable_routes),
+    ok.
 
 declare(ExchangeName, Type, Durable, AutoDelete, Args) ->
     Exchange = #exchange{name = ExchangeName,

src/rabbit_misc.erl

@@ -46,6 +46,7 @@
 -export([ensure_ok/2]).
 -export([localnode/1, tcp_name/3]).
 -export([intersperse/2, upmap/2, map_in_order/2]).
+-export([table_foreach/2]).
 -export([dirty_read_all/1, dirty_foreach_key/2, dirty_dump_log/1]).
 -export([append_file/2, ensure_parent_dirs_exist/1]).
 -export([format_stderr/2]).
@@ -97,6 +98,7 @@
 -spec(intersperse/2 :: (A, [A]) -> [A]).
 -spec(upmap/2 :: (fun ((A) -> B), [A]) -> [B]).
 -spec(map_in_order/2 :: (fun ((A) -> B), [A]) -> [B]).
+-spec(table_foreach/2 :: (fun ((any()) -> any()), atom()) -> 'ok').
 -spec(dirty_read_all/1 :: (atom()) -> [any()]).
 -spec(dirty_foreach_key/2 :: (fun ((any()) -> any()), atom()) ->
              'ok' | 'aborted').
@@ -295,6 +297,21 @@ map_in_order(F, L) ->
     lists:reverse(
       lists:foldl(fun (E, Acc) -> [F(E) | Acc] end, [], L)).
 
+%% For each entry in a table, execute a function in a transaction.
+%% This is often far more efficient than wrapping a tx around the lot.
+%%
+%% We ignore entries that have been modified or removed.
+table_foreach(F, TableName) ->
+    lists:foreach(
+      fun (E) -> execute_mnesia_transaction(
+                   fun () -> case mnesia:match_object(TableName, E, read) of
+                                 [] -> ok;
+                                 _  -> F(E)
+                             end
+                   end)
+      end, dirty_read_all(TableName)),
+    ok.
+
 dirty_read_all(TableName) ->
     mnesia:dirty_select(TableName, [{'$1',[],['$1']}]).