mongodb - 使用Pymongo的并行扫描时找不到光标

我有一个mongo数据库，其中包含我用pymongo处理的3000.000个文档。我想遍历所有文档，而不更新集合。
我试着用四根线：

cursors = db[collection].parallel_scan(CURSORS_NUM)
threads = [
    threading.Thread(target=process_cursor, args=(cursor, )) for cursor in cursors
]

for thread in threads:
    thread.start()

for thread in threads:
    thread.join()

以及进程光标函数：

def process_cursor(cursor):
    for document in cursor:
        dosomething(document)

在处理文档一段时间后，我收到错误消息：

  File "extendDocuments.py", line 133, in process_cursor
    for document in cursor:
  File "/usr/local/lib/python2.7/dist-packages/pymongo/command_cursor.py", line 165, in next
    if len(self.__data) or self._refresh():
  File "/usr/local/lib/python2.7/dist-packages/pymongo/command_cursor.py", line 142, in _refresh
    self.__batch_size, self.__id))
  File "/usr/local/lib/python2.7/dist-packages/pymongo/command_cursor.py", line 110, in __send_message
    *self.__decode_opts)
  File "/usr/local/lib/python2.7/dist-packages/pymongo/helpers.py", line 97, in _unpack_response
    cursor_id)
CursorNotFound: cursor id '116893918402' not valid at server

如果我使用find（）来代替，我可以将超时设置为false以避免出现这种情况。
我能用并行扫描得到的游标做些类似的事情吗？

最佳答案

当前无法关闭ParallelCollectionScan返回的游标的空闲超时。我打开了一个功能请求：
https://jira.mongodb.org/browse/SERVER-15042