1 files changed, 8 insertions, 0 deletions
diff --git a/synapse/notifier.py b/synapse/notifier.py
index b9531007e2..24b4e6649f 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -38,6 +38,7 @@ from synapse.api.constants import EventTypes, HistoryVisibility, Membership
 from synapse.api.errors import AuthError
 from synapse.events import EventBase
 from synapse.handlers.presence import format_user_presence_state
+from synapse.logging import issue9533_logger
 from synapse.logging.context import PreserveLoggingContext
 from synapse.logging.opentracing import log_kv, start_active_span
 from synapse.logging.utils import log_function
@@ -426,6 +427,13 @@ class Notifier:
             for room in rooms:
                 user_streams |= self.room_to_user_streams.get(room, set())
 
+            if stream_key == "to_device_key":
+                issue9533_logger.debug(
+                    "to-device messages stream id %s, awaking streams for %s",
+                    new_token,
+                    users,
+                )
+
             time_now_ms = self.clock.time_msec()
             for user_stream in user_streams:
                 try: