Python Sqlalchemy属性错误：'；非类型'；对象没有属性'_getter'；

在我设置的实时系统中随机接收上述错误（到目前为止，平均每月一次）。问题是错误不会持续（即，当我触摸app.wsgi文件时会消失），因此很难确定是什么导致了问题。它似乎失败的查询是登录时使用的第一个查询。 i、 e

这在大多数情况下都可以正常工作，单元测试中已经介绍了这一点

完整回溯错误如下所示：

[:error]     File "/path/to/my/python/file.py", line 23, in get_user_object
[:error]       user = db_session.query(Users).filter(Users.username == username, Users.password == password).first()
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2445, in first
[:error]       ret = list(self[0:1])
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2281, in __getitem__
[:error]       return list(res)
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/loading.py", line 84, in instances
[:error]       util.raise_from_cause(err)
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 199, in raise_from_cause
[:error]       reraise(type(exception), exception, tb=exc_tb)
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/loading.py", line 51, in instances
[:error]       for query_entity in query._entities
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 3312, in row_processor
[:error]       polymorphic_discriminator=self._polymorphic_discriminator
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/loading.py", line 313, in _instance_processor
[:error]       getter = result._getter(col)
[:error]     File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/result.py", line 495, in _getter
[:error]       return self._metadata._getter(key)
[:error]   AttributeError: 'NoneType' object has no attribute '_getter'

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这个问题是通过做一个简单的测试来解决的

pip install sqlalchemy --upgrade

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按照rmn在评论中的建议，在给定的实时系统上。

您有异常的完整回溯吗？现在包括了，请参见上文。您使用的是什么版本的SQLAlchemy？看起来像此错误：。它是在1.0.7.Perfecto中修复的，我来试试。干杯

pip install sqlalchemy --upgrade