屈服期间的sqlalchemy光标错误

Question

我得到以下错误：

Traceback (most recent call last):
    main()
    for item in session.query(Item).yield_per(10):
    fetch = cursor.fetchmany(self._yield_per)
    self.cursor, self.context)
    l = self.process_rows(self._fetchmany_impl(size))
    row = self._fetchone_impl()
    self.__buffer_rows()
    self.__rowbuffer = collections.deque(self.cursor.fetchmany(size))
sqlalchemy.exc.ProgrammingError: (ProgrammingError) named cursor isn't valid anymore None None

我怀疑调用session.commit（）会干扰.yield\u per

sessionmaker_ = sessionmaker(autocommit=False, autoflush=False, bind=engine)
session = scoped_session(sessionmaker_)

def foo(item):
  # DO something to the item 
  session.add(item)
  session.commit()

def main():
  for item in session.query(Item).yield_per(5):
    foo(item)

知道吗？