merge default (again)bug25192

2 files changed, 11 insertions, 18 deletions

diff --git a/src/rabbit_mirror_queue_coordinator.erl b/src/rabbit_mirror_queue_coordinator.erl
index 676cb519..72dcfc95 100644
--- a/src/rabbit_mirror_queue_coordinator.erl
+++ b/src/rabbit_mirror_queue_coordinator.erl
@@ -397,8 +397,6 @@ members_changed([_CPid], _Births, []) ->
 members_changed([CPid], _Births, Deaths) ->
     ok = gen_server2:cast(CPid, {gm_deaths, Deaths}).
 
-handle_msg([_CPid], _From, master_changed) ->
-    ok;
 handle_msg([CPid], _From, request_depth = Msg) ->
     ok = gen_server2:cast(CPid, Msg);
 handle_msg([CPid], _From, {ensure_monitoring, _Pids} = Msg) ->
diff --git a/src/rabbit_mirror_queue_slave.erl b/src/rabbit_mirror_queue_slave.erl
index 61423202..931a7f90 100644
--- a/src/rabbit_mirror_queue_slave.erl
+++ b/src/rabbit_mirror_queue_slave.erl
@@ -173,7 +173,6 @@ handle_call({deliver, Delivery, true}, From, State) ->
 
 handle_call({gm_deaths, Deaths}, From,
             State = #state { q          = #amqqueue { name = QueueName },
-                             gm         = GM,
                              master_pid = MPid }) ->
     %% The GM has told us about deaths, which means we're not going to
     %% receive any more messages from GM
@@ -196,12 +195,6 @@ handle_call({gm_deaths, Deaths}, From,
                     %% master has changed to not us.
                     gen_server2:reply(From, ok),
                     erlang:monitor(process, Pid),
-                    %% GM is lazy. So we know of the death of the
-                    %% slave since it is a neighbour of ours, but
-                    %% until a message is sent, not all members will
-                    %% know. That might include the new master. So
-                    %% broadcast a no-op message to wake everyone up.
-                    ok = gm:broadcast(GM, master_changed),
                     noreply(State #state { master_pid = Pid })
             end
     end;
@@ -252,8 +245,8 @@ handle_info(timeout, State) ->
     noreply(backing_queue_timeout(State));
 
 handle_info({'DOWN', _MonitorRef, process, MPid, _Reason},
-           State = #state { gm = GM, master_pid = MPid }) ->
-    ok = gm:broadcast(GM, {process_death, MPid}),
+            State = #state { gm = GM, master_pid = MPid }) ->
+    ok = gm:broadcast(GM, process_death),
     noreply(State);
 
 handle_info({'DOWN', _MonitorRef, process, ChPid, _Reason}, State) ->
@@ -340,16 +333,21 @@ joined([SPid], _Members) -> SPid ! {joined, self()}, ok.
 members_changed([_SPid], _Births,     []) -> ok;
 members_changed([ SPid], _Births, Deaths) -> inform_deaths(SPid, Deaths).
 
-handle_msg([_SPid], _From, master_changed) ->
-    ok;
 handle_msg([_SPid], _From, request_depth) ->
     %% This is only of value to the master
     ok;
 handle_msg([_SPid], _From, {ensure_monitoring, _Pid}) ->
     %% This is only of value to the master
     ok;
-handle_msg([SPid], _From, {process_death, Pid}) ->
-    inform_deaths(SPid, [Pid]);
+handle_msg([_SPid], _From, process_death) ->
+    %% Since GM is by nature lazy we need to make sure there is some
+    %% traffic when a master dies, to make sure we get informed of the
+    %% death. That's all process_death does, create some traffic. We
+    %% must not take any notice of the master death here since it
+    %% comes without ordering guarantees - there could still be
+    %% messages from the master we have yet to receive. When we get
+    %% members_changed, then there will be no more messages.
+    ok;
 handle_msg([CPid], _From, {delete_and_terminate, _Reason} = Msg) ->
     ok = gen_server2:cast(CPid, {gm, Msg}),
     {stop, {shutdown, ring_shutdown}};
@@ -449,9 +447,6 @@ promote_me(From, #state { q                   = Q = #amqqueue { name = QName },
                    rabbit_mirror_queue_master:depth_fun()),
     true = unlink(GM),
     gen_server2:reply(From, {promote, CPid}),
-    %% TODO this has been in here since the beginning, but it's not
-    %% obvious if it is needed. Investigate...
-    ok = gm:confirmed_broadcast(GM, master_changed),
 
     %% Everything that we're monitoring, we need to ensure our new
     %% coordinator is monitoring.