1 files changed, 7 insertions, 0 deletions
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 24ff872dad..37bb28e6cf 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -791,6 +791,13 @@ class SQLBaseStore(object):
         return result[0] if result else None
 
 
+class _RollbackButIsFineException(Exception):
+    """ This exception is used to rollback a transaction without implying
+    something went wrong.
+    """
+    pass
+
+
 class Table(object):
     """ A base class used to store information about a particular table.
     """