pymongo.errors.CursorNotFound: Cursor not found

原因：在cursor上长时间没有进行操作，会引发cursor在mongodb服务端超时
解决办法：设置_no_cursor_timeout = True_，永不超时，游标连接不会主动关闭，需要手动关闭

pymongo

https://api.mongodb.com/python/current/migrate-to-pymongo3.html?highlight=timeout#timeout-replaced-by-no-cursor-timeout

demos = db['demo'].find({}, {"_id": 0}, no_cursor_timeout=True)  # 旧版本 timeout=False
for cursor in demos:
        do_something()
demo.close() # 关闭游标

mongoengine

http://docs.mongoengine.org/apireference.html?highlight=timeout#mongoengine.queryset.QuerySet.timeout

for each in article.objects(**context).timeout(False):
    do_something()

• https://www.jianshu.com/p/a8551bd17b5b