3

更新：刚刚发现 echo_pool=True 只显示重大事件，使用 echo_pool="debug" 代替。

我必须显式关闭引擎连接，否则TimeoutError: QueuePool limit of size 5 overflow 10 reached, connection timed out, timeout 30在使用nosetest 和sqlalchemy 时会出错。

我正在关注有关如何将Session 加入外部事务的 SqlAlchemy 文档。唯一的区别是我使用的是作用域会话。这是有问题的代码：

import unittest

from sqlalchemy import create_engine

from myapp.mymodel import Session

engine = create_engine(
    '<REDACTED>',
    echo = False,
    # To make it faster to fail, but also fails with the default options
    # pool_size=2,
    # max_overflow=0,
    # echo_pool="debug",
    # pool_timeout=10,
)


class MyTest(unittest.TestCase):

    def setUp(self):
        self.connection = engine.connect()

        # begin a non-ORM transaction
        self.trans = self.connection.begin()

        # bind an individual Session to the connection
        Session.configure(bind=self.connection)

        self.addCleanup(self._teardown)

    def _teardown(self):
        """Rollback the db.

        Added to the list of cleanup by setUp, so that subclass do not have to
        call super() on tearDown.
        """

        # Rollback database
        self.trans.rollback()

        # Session must be closed BEFORE being removed
        Session.close()
        Session.remove()
        # If I don't do that, I get TimeOut
        # self.connection.close()

这是echo_pool调试输出：

2012-09-11 12:34:28,506 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bae1e20>
2012-09-11 12:34:28,514 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bae1e20> checked out from pool
2012-09-11 12:34:29,664 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bc61c20>
2012-09-11 12:34:29,665 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bc61c20> checked out from pool
2012-09-11 12:34:30,368 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bc9ea20>
2012-09-11 12:34:30,369 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bc9ea20> checked out from pool
2012-09-11 12:34:31,042 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bcd6820>
2012-09-11 12:34:31,043 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bcd6820> checked out from pool
2012-09-11 12:34:31,775 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bcbd820>
2012-09-11 12:34:31,775 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bcbd820> checked out from pool
2012-09-11 12:34:32,439 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bcc2220>
2012-09-11 12:34:32,439 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bcc2220> checked out from pool
2012-09-11 12:34:33,129 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd0e220>
2012-09-11 12:34:33,129 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd0e220> checked out from pool
2012-09-11 12:34:33,802 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd1e420>
2012-09-11 12:34:33,802 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd1e420> checked out from pool
2012-09-11 12:34:34,590 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bcf6a20>
2012-09-11 12:34:34,590 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bcf6a20> checked out from pool
2012-09-11 12:34:35,452 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd53420>
2012-09-11 12:34:35,452 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd53420> checked out from pool
2012-09-11 12:34:36,276 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd32420>
2012-09-11 12:34:36,276 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd32420> checked out from pool
2012-09-11 12:34:36,970 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd80420>
2012-09-11 12:34:36,971 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd80420> checked out from pool
2012-09-11 12:34:37,639 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bda9020>
2012-09-11 12:34:37,640 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bda9020> checked out from pool
2012-09-11 12:34:37,664 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bdc3c20>
2012-09-11 12:34:37,664 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bdc3c20> checked out from pool
2012-09-11 12:34:37,675 DEBUG sqlalchemy.pool.QueuePool Created new connection <_mysql.connection open to '127.0.0.1' at 7f938bd95e20>
2012-09-11 12:34:37,675 DEBUG sqlalchemy.pool.QueuePool Connection <_mysql.connection open to '127.0.0.1' at 7f938bd95e20> checked out from pool

谢谢！

4

1 回答 1

2

我在 sqlalchemy 的小组上问了同样的问题。

所以是的，你确实需要明确地关闭连接，根据 Michael Bayer 的说法：

当您使用 unittest 运行测试时，unittest 会创建您的测试类的一个新实例，这意味着所有这些测试类实例都将存在 self.connection 并且不会返回到池中。

https://groups.google.com/forum/?fromgroups=#!topic/sqlalchemy/eiQTXKn5ai8

于 2012-09-12T08:09:13.370 回答