芹菜工人无法访问数据库

Question

我正在运行Celery和django-celery的最新稳定版本。我已经定义了一个传递主键的任务，获取与该键相关联的对象，并对其进行处理。当我直接调用函数时，这一切都很有效，但是当我将消息放入队列（MongoDB）时，工作程序在访问数据库时失败（使用附加的堆栈跟踪）。还有其他人遇到过这个问题吗？

[2012-05-04 12:01:23,673: INFO/MainProcess] Got task from broker: app.tasks.process_model[71934fab-b3a2-4847-bb3e-00484d77c6c7]
[2012-05-04 12:01:25,202: INFO/PoolWorker-4] child process calling self.run()
[2012-05-04 12:01:35,618: ERROR/MainProcess] Task coupons.tasks.queue_print_image[71934fab-b3a2-4847-bb3e-00484d77c6c7] raised exception: WorkerLostError('Worker exited prematurely.',)
Traceback (most recent call last):
  File "/Users/<user>/Envs/cf/lib/python2.7/site-packages/celery/concurrency/processes/pool.py", line 634, in _join_exited_workers
    raise WorkerLostError("Worker exited prematurely.")
WorkerLostError: Worker exited prematurely.