faster remove

oml/item/models.py

@@ -104,6 +104,15 @@ class Item(db.Model):
         cls.query.filter(cls.id.in_(ids)).delete(synchronize_session=False)
         state.db.session.expire_all()
 
+    @classmethod
+    def remove_without_user(cls):
+        q = user_items.select()
+        owned_ids = {i['item_id'] for i in state.db.session.execute(q)}
+        ids = {i.id for i in cls.query.options(load_only('id'))}
+        remove = ids - owned_ids
+        if remove:
+            cls.remove_many(remove)
+
     def add_user(self, user):
         if not user in self.users:
             self.users.append(user)