Sliding sync: don't fetch room summary for named rooms. (#17683)

For rooms with a name we can skip fetching a full room summary, as we
don't need to calculate heroes, and instead just fetch the room counts
directly.

This also changes things to not return counts and heroes for non-joined
rooms. For left/banned rooms we were returning zero values anyway, and
for invite/knock rooms we don't really want to leak such information
(even if some of is included in the stripped state).

1 files changed, 2 insertions, 0 deletions

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py

index d22160b85c..d6deb077c8 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -112,6 +112,7 @@ class SQLBaseStore(metaclass=ABCMeta):
             self._attempt_to_invalidate_cache(
                 "get_number_joined_users_in_room", (room_id,)
             )
+            self._attempt_to_invalidate_cache("get_member_counts", (room_id,))
             self._attempt_to_invalidate_cache("get_local_users_in_room", (room_id,))
 
             # There's no easy way of invalidating this cache for just the users
@@ -153,6 +154,7 @@ class SQLBaseStore(metaclass=ABCMeta):
         self._attempt_to_invalidate_cache("get_current_hosts_in_room", (room_id,))
         self._attempt_to_invalidate_cache("get_users_in_room_with_profiles", (room_id,))
         self._attempt_to_invalidate_cache("get_number_joined_users_in_room", (room_id,))
+        self._attempt_to_invalidate_cache("get_member_counts", (room_id,))
         self._attempt_to_invalidate_cache("get_local_users_in_room", (room_id,))
         self._attempt_to_invalidate_cache("does_pair_of_users_share_a_room", None)
         self._attempt_to_invalidate_cache("get_user_in_room_with_profile", None)