Pymongo 断言错误：ID 不匹配

Question

我使用的是：

• MongoDB 1.6.5
• Pymongo 1.9
• Python 2.6.6

我有三种类型的守护进程。第一种是从网上加载数据，第二种是分析数据并保存结果，第三种是对结果进行分组。它们都在使用MongoDB。

有时候，第三个守护进程会抛出很多异常，像这样（通常是在数据库中有大量数据的时候）：

Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/gevent-0.13.1-py2.6-linux-x86_64.egg/gevent/greenlet.py", line 405, in run
    result = self._run(*self.args, **self.kwargs)
  File "/data/www/spider/daemon/scripts/mainconverter.py", line 72, in work
    for item in res:
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 601, in next
    if len(self.__data) or self._refresh():
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 564, in _refresh
    self.__query_spec(), self.__fields))
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/cursor.py", line 521, in __send_message
    **kwargs)
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 743, in _send_message_with_response
    return self.__send_and_receive(message, sock)
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 724, in __send_and_receive
    return self.__receive_message_on_socket(1, request_id, sock)
  File "/usr/local/lib/python2.6/dist-packages/pymongo-1.9_-py2.6-linux-x86_64.egg/pymongo/connection.py", line 714, in __receive_message_on_socket
    struct.unpack("<i", header[8:12])[0])
AssertionError: ids don't match -561338340 0
<Greenlet at 0x2baa628: <bound method Worker.work of <scripts.mainconverter.Worker object at 0x2ba8450>>> failed with AssertionError

有没有人能告诉我是什么原因导致这个异常，以及如何解决这个问题。

谢谢。

Answer 1

这可能是一个线程问题，跟你如何使用工作线程和gevent协程有关。看起来pymongo的连接对象正在读取一个它并没有发出的请求的响应。