get heartbeat monitor to pause when it should

On 'default' we kick off another prim_inet:async_recv *before*
handling the frame we've just received. This is done for performance
reasons - essentially we are reading ahead - and leads to the following
sequence of events:

1. receive memory alarm -> change state to 'blocking'
2. receive a 'publish' method frame
3. kick off another prim_inet:async_recv
4. handle frame, detecting that it is a 'publish' frame and thus
   changing the state to 'blocked'
5. receive the frame header for another frame (e.g. the message
   header, or could be something on another channel, or a heartbeat)
6. since the state is 'blocked' and we pause the heartbeat
   monitor and *don't* kick off another prim_inet:async_recv

On this branch we don't read ahead since a) that would complicate the
logic a fair bit, and b) we could end up draining a fair chunk of data
from the socket, rather than just a frame header. As a result we need
to make sure the heartbeat monitor gets paused as soon as we
transition to the 'blocked' state.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/rabbit_reader.erl b/src/rabbit_reader.erl
index 792102681a..e210dba182 100644
--- a/src/rabbit_reader.erl
+++ b/src/rabbit_reader.erl
@@ -521,8 +521,8 @@ handle_input({frame_payload, Type, Channel, PayloadSize},
              PayloadAndMarker, State) ->
     case PayloadAndMarker of
         <<Payload:PayloadSize/binary, ?FRAME_END>> ->
-            handle_frame(Type, Channel, Payload,
-                         switch_callback(State, frame_header, 7));
+            switch_callback(handle_frame(Type, Channel, Payload, State),
+                            frame_header, 7);
         _ ->
             throw({bad_payload, Type, Channel, PayloadSize, PayloadAndMarker})
     end;