Log actual number of entries deleted

synapse/storage/_base.py

@@ -1261,7 +1261,8 @@ class SQLBaseStore(object):
             " AND ".join("%s = ?" % (k,) for k in keyvalues),
         )
 
-        return txn.execute(sql, list(keyvalues.values()))
+        txn.execute(sql, list(keyvalues.values()))
+        return txn.rowcount
 
     def _simple_delete_many(self, table, column, iterable, keyvalues, desc):
         return self.runInteraction(
@@ -1280,9 +1281,12 @@ class SQLBaseStore(object):
             column : column name to test for inclusion against `iterable`
             iterable : list
             keyvalues : dict of column names and values to select the rows with
+
+        Returns:
+            int: Number rows deleted
         """
         if not iterable:
-            return
+            return 0
 
         sql = "DELETE FROM %s" % table
 
@@ -1297,7 +1301,9 @@ class SQLBaseStore(object):
 
         if clauses:
             sql = "%s WHERE %s" % (sql, " AND ".join(clauses))
-        return txn.execute(sql, values)
+        txn.execute(sql, values)
+
+        return txn.rowcount
 
     def _get_cache_dict(
         self, db_conn, table, entity_column, stream_column, max_value, limit=100000

synapse/storage/events.py

@@ -2476,7 +2476,7 @@ class EventsStore(
 
             logger.info("Deleting up to %d forward extremities", len(to_delete))
 
-            self._simple_delete_many_txn(
+            deleted = self._simple_delete_many_txn(
                 txn=txn,
                 table="event_forward_extremities",
                 column="event_id",
@@ -2484,7 +2484,9 @@ class EventsStore(
                 keyvalues={},
             )
 
-            if to_delete:
+            logger.info("Deleted %d forward extremities", deleted)
+
+            if deleted:
                 # We now need to invalidate the caches of these rooms
                 rows = self._simple_select_many_txn(
                     txn,