我正在将Celery与Amazon SQS一起使用，我在日志中看到了大量这些内容：
[2013-06-19 19:03:42,890: ERROR/MainProcess] Pool callback raised exception: KeyError('8a8fe51c-b69f-498e-95c1-f037e2f2d4a8',)
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/billiard/pool.py", line 129, in safe_apply_callback
fun(*args)
File "/usr/local/lib/python2.7/dist-packages/celery/worker/job.py", line 301, in on_accepted
self.acknowledge()
File "/usr/local/lib/python2.7/dist-packages/celery/worker/job.py", line 439, in acknowledge
self.on_ack(logger, self.connection_errors)
File "/usr/local/lib/python2.7/dist-packages/kombu/transport/base.py", line 98, in ack_log_error
self.ack()
File "/usr/local/lib/python2.7/dist-packages/kombu/transport/base.py", line 93, in ack
self.channel.basic_ack(self.delivery_tag)
File "/usr/local/lib/python2.7/dist-packages/kombu/transport/SQS.py", line 252, in basic_ack
delivery_info = self.qos.get(delivery_tag).delivery_info
File "/usr/local/lib/python2.7/dist-packages/kombu/transport/virtual/__init__.py", line 127, in get
return self._delivered[delivery_tag]
KeyError: '8a8fe51c-b69f-498e-95c1-f037e2f2d4a8'
我试图谷歌这个，似乎没有人真正知道它来自哪里？有谁知道最近发生了什么？我注意到一些奇怪的行为，任务失败，然后它一次又一次地重试相同的任务。过了一段时间，它不仅会重试，而且甚至不会在日志中显示错误（或任何日志声明）。它只是说它有一个任务，它会尝试它。我不确定发生了什么事？
我只是使用以下方法进行清除：
from celery.task.control import discard_all
discard_all()
以某种方式，任务又重新开始了！有没有人知道这有甚么可能？