1 files changed, 32 insertions, 4 deletions
diff --git a/synapse/replication/tcp/commands.py b/synapse/replication/tcp/commands.py
index 5a6b734094..e4eec643f7 100644
--- a/synapse/replication/tcp/commands.py
+++ b/synapse/replication/tcp/commands.py
@@ -207,30 +207,32 @@ class UserSyncCommand(Command):
 
     Format::
 
-        USER_SYNC <user_id> <state> <last_sync_ms>
+        USER_SYNC <instance_id> <user_id> <state> <last_sync_ms>
 
     Where <state> is either "start" or "stop"
     """
 
     NAME = "USER_SYNC"
 
-    def __init__(self, user_id, is_syncing, last_sync_ms):
+    def __init__(self, instance_id, user_id, is_syncing, last_sync_ms):
+        self.instance_id = instance_id
         self.user_id = user_id
         self.is_syncing = is_syncing
         self.last_sync_ms = last_sync_ms
 
     @classmethod
     def from_line(cls, line):
-        user_id, state, last_sync_ms = line.split(" ", 2)
+        instance_id, user_id, state, last_sync_ms = line.split(" ", 3)
 
         if state not in ("start", "end"):
             raise Exception("Invalid USER_SYNC state %r" % (state,))
 
-        return cls(user_id, state == "start", int(last_sync_ms))
+        return cls(instance_id, user_id, state == "start", int(last_sync_ms))
 
     def to_line(self):
         return " ".join(
             (
+                self.instance_id,
                 self.user_id,
                 "start" if self.is_syncing else "end",
                 str(self.last_sync_ms),
@@ -238,6 +240,30 @@ class UserSyncCommand(Command):
         )
 
 
+class ClearUserSyncsCommand(Command):
+    """Sent by the client to inform the server that it should drop all
+    information about syncing users sent by the client.
+
+    Mainly used when client is about to shut down.
+
+    Format::
+
+        CLEAR_USER_SYNC <instance_id>
+    """
+
+    NAME = "CLEAR_USER_SYNC"
+
+    def __init__(self, instance_id):
+        self.instance_id = instance_id
+
+    @classmethod
+    def from_line(cls, line):
+        return cls(line)
+
+    def to_line(self):
+        return self.instance_id
+
+
 class FederationAckCommand(Command):
     """Sent by the client when it has processed up to a given point in the
     federation stream. This allows the master to drop in-memory caches of the
@@ -398,6 +424,7 @@ _COMMANDS = (
     InvalidateCacheCommand,
     UserIpCommand,
     RemoteServerUpCommand,
+    ClearUserSyncsCommand,
 )  # type: Tuple[Type[Command], ...]
 
 # Map of command name to command type.
@@ -420,6 +447,7 @@ VALID_CLIENT_COMMANDS = (
     ReplicateCommand.NAME,
     PingCommand.NAME,
     UserSyncCommand.NAME,
+    ClearUserSyncsCommand.NAME,
     FederationAckCommand.NAME,
     RemovePusherCommand.NAME,
     InvalidateCacheCommand.NAME,