SQLAlchemy连接池关闭异常

Question

有没有人知道为什么每当关闭 SQLAlchemy 池中的连接（conn.close()）时，我会收到以下异常：

ERROR:Exception during reset or similar       
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 631, in _finalize_fairy
    fairy._reset(pool)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 771, in _reset
    pool._dialect.do_rollback(self)
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 83, in do_rollback
    dbapi_connection.rollback()
File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 850, in __getattr__
    return getattr(self.connection, key)
AttributeError: 'Connection' object has no attribute 'rollback'

我正在使用SQLAlchemy==1.0.6连接到mysql数据库，这是我的代码部分：

self.__engine = create_engine("mysql+mysqldb://%s:%s@%s/%s?charset=utf8&use_unicode=0" %(config['db_user'], config['db_passwd'], config['db_host'], config['db']), pool_recycle=3600)
self.__mypool = pool.QueuePool(self.__getConn, pool_size=config['db_pool_size'])
conn = self.__mypool.connect()
results = conn.execute(statement, values)
conn.close()

- Ken

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请查看这个答案。 - doru

问题与您提供的答案不同，但还是谢谢。我已经找到了问题所在。我可能会回答我的问题，供其他人参考。 - Ken

Answer 1

在当前版本的SQLAlchemy中（之前的某些版本可以使用），队列池已经集成到create_engine()中。它不喜欢单独创建QueuePool()。以下更改解决了问题：

self.__mypool = create_engine("mysql+mysqldb://%s:%s@%s/%s?charset=utf8&use_unicode=0" %(config['db_user'], config['db_passwd'], config['db_host'], config['db']), pool_size=config['db_pool_size'], pool_recycle=3600)
conn = self.__mypool.connect()
results = conn.execute(statement, values)
conn.close()

- Ken