1 files changed, 20 insertions, 0 deletions
diff --git a/synapse/storage/databases/main/room.py b/synapse/storage/databases/main/room.py
index 064c332fb7..672c9a03fc 100644
--- a/synapse/storage/databases/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -1217,6 +1217,26 @@ class RoomWorkerStore(CacheInvalidationWorkerStore):
         )
         self._invalidate_cache_and_stream(txn, self.is_partial_state_room, (room_id,))
 
+        # We now delete anything from `device_lists_remote_pending` with a
+        # stream ID less than the minimum
+        # `partial_state_rooms.device_lists_stream_id`, as we no longer need them.
+        device_lists_stream_id = DatabasePool.simple_select_one_onecol_txn(
+            txn,
+            table="partial_state_rooms",
+            keyvalues={},
+            retcol="MIN(device_lists_stream_id)",
+            allow_none=True,
+        )
+        if device_lists_stream_id is None:
+            # There are no rooms being currently partially joined, so we delete everything.
+            txn.execute("DELETE FROM device_lists_remote_pending")
+        else:
+            sql = """
+                DELETE FROM device_lists_remote_pending
+                WHERE stream_id <= ?
+            """
+            txn.execute(sql, (device_lists_stream_id,))
+
     @cached()
     async def is_partial_state_room(self, room_id: str) -> bool:
         """Checks if this room has partial state.