1 files changed, 1 insertions, 0 deletions
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index e20c5c5302..feaa6cdd07 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -499,6 +499,7 @@ class DatabasePool:
     """
 
     _TXN_ID = 0
+    engine: BaseDatabaseEngine
 
     def __init__(
         self,