simplify queue startup

by going through the same three-step sequence (start process,
init_backing_queue, sync) in both recovery and creation

2 files changed, 15 insertions, 20 deletions

diff --git a/src/rabbit_amqqueue.erl b/src/rabbit_amqqueue.erl
index 4e12bb7d47..668f4ae256 100644
--- a/src/rabbit_amqqueue.erl
+++ b/src/rabbit_amqqueue.erl
@@ -144,7 +144,7 @@ find_durable_queues() ->
       end).
 
 recover_durable_queues(DurableQueues) ->
-    Qs = [start_queue_process(Q, false) || Q <- DurableQueues],
+    Qs = [start_queue_process(Q) || Q <- DurableQueues],
     %% Issue inits to *all* the queues so that they all init at the same time
     [ok = gen_server2:cast(Q#amqqueue.pid, init_backing_queue) || Q <- Qs],
     [ok = gen_server2:call(Q#amqqueue.pid, sync, infinity) || Q <- Qs],
@@ -157,7 +157,9 @@ declare(QueueName, Durable, AutoDelete, Args) ->
                                       durable = Durable,
                                       auto_delete = AutoDelete,
                                       arguments = Args,
-                                      pid = none}, true),
+                                      pid = none}),
+    ok = gen_server2:cast(Q#amqqueue.pid, init_backing_queue),
+    ok = gen_server2:call(Q#amqqueue.pid, sync, infinity),
     internal_declare(Q, true).
 
 internal_declare(Q = #amqqueue{name = QueueName}, WantDefaultBinding) ->
@@ -194,8 +196,8 @@ store_queue(Q = #amqqueue{durable = false}) ->
     ok = mnesia:write(rabbit_queue, Q, write),
     ok.
 
-start_queue_process(Q, InitBackingQueue) ->
-    {ok, Pid} = rabbit_amqqueue_sup:start_child([Q, InitBackingQueue]),
+start_queue_process(Q) ->
+    {ok, Pid} = rabbit_amqqueue_sup:start_child([Q]),
     Q#amqqueue{pid = Pid}.
 
 add_default_binding(#amqqueue{name = QueueName}) ->
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index b10baacb46..10e1193f02 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -39,7 +39,7 @@
 -define(SYNC_INTERVAL,                 5). %% milliseconds
 -define(RAM_DURATION_UPDATE_INTERVAL,  5000).
 
--export([start_link/2, info_keys/0]).
+-export([start_link/1, info_keys/0]).
 
 -export([init/1, terminate/2, code_change/3, handle_call/3, handle_cast/2,
          handle_info/2, handle_pre_hibernate/1]).
@@ -94,14 +94,14 @@
 
 %%----------------------------------------------------------------------------
 
-start_link(Q, InitBackingQueue) ->
-    gen_server2:start_link(?MODULE, [Q, InitBackingQueue], []).
+start_link(Q) ->
+    gen_server2:start_link(?MODULE, [Q], []).
 
 info_keys() -> ?INFO_KEYS.
 
 %%----------------------------------------------------------------------------
 
-init([Q, InitBQ]) ->
+init([Q]) ->
     ?LOGDEBUG("Queue starting - ~p~n", [Q]),
     process_flag(trap_exit, true),
     ok = file_handle_cache:register_callback(
@@ -115,7 +115,7 @@ init([Q, InitBQ]) ->
             exclusive_consumer = none,
             has_had_consumers = false,
             backing_queue = BQ,
-            backing_queue_state = maybe_init_backing_queue(InitBQ, BQ, Q),
+            backing_queue_state = undefined,
             backing_queue_timeout_fun = undefined,
             active_consumers = queue:new(),
             blocked_consumers = queue:new(),
@@ -123,12 +123,6 @@ init([Q, InitBQ]) ->
             rate_timer_ref = undefined}, hibernate,
      {backoff, ?HIBERNATE_AFTER_MIN, ?HIBERNATE_AFTER_MIN, ?DESIRED_HIBERNATE}}.
 
-maybe_init_backing_queue(
-  true, BQ, #amqqueue{name = QName, durable = IsDurable}) ->
-    BQ:init(QName, IsDurable);
-maybe_init_backing_queue(false, _BQ, _Q) ->
-    undefined.
-
 terminate(shutdown,      State) ->
     terminate_shutdown(terminate, State);
 terminate({shutdown, _}, State) ->
@@ -731,11 +725,10 @@ handle_call({claim_queue, ReaderPid}, _From,
 handle_call({maybe_run_queue_via_backing_queue, Fun}, _From, State) ->
     reply(ok, maybe_run_queue_via_backing_queue(Fun, State)).
 
-
-handle_cast(init_backing_queue, State = #q{backing_queue_state = undefined,
-                                           backing_queue = BQ, q = Q}) ->
-    noreply(State#q{backing_queue_state =
-                        maybe_init_backing_queue(true, BQ, Q)});
+handle_cast(init_backing_queue,
+            State = #q{q = #amqqueue{name = QName, durable = IsDurable},
+                       backing_queue_state = undefined, backing_queue = BQ}) ->
+    noreply(State#q{backing_queue_state = BQ:init(QName, IsDurable)});
 
 handle_cast(init_backing_queue, State) ->
     noreply(State);