1 files changed, 13 insertions, 1 deletions
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 860b03f7b9..4fc9ff92e5 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -55,6 +55,11 @@ class FederationRemoteSendQueue(object):
         self.notifier = hs.get_notifier()
         self.is_mine_id = hs.is_mine_id
 
+        # We may have multiple federation sender instances, so we need to track
+        # their positions separately.
+        self._sender_instances = hs.config.federation.federation_shard_config.instances
+        self._sender_positions = {}
+
         # Pending presence map user_id -> UserPresenceState
         self.presence_map = {}  # type: Dict[str, UserPresenceState]
 
@@ -261,7 +266,14 @@ class FederationRemoteSendQueue(object):
     def get_current_token(self):
         return self.pos - 1
 
-    def federation_ack(self, token):
+    def federation_ack(self, instance_name, token):
+        if self._sender_instances:
+            # If we have configured multiple federation sender instances we need
+            # to track their positions separately, and only clear the queue up
+            # to the token all instances have acked.
+            self._sender_positions[instance_name] = token
+            token = min(self._sender_positions.values())
+
         self._clear_queue_before_pos(token)
 
     async def get_replication_rows(