为什么time.sleep完全停止执行？

Question

下面的函数用于运行循环20分钟，如果可用的话处理SQL任务。为了避免在没有任何需要处理的情况下调用过多的SQL，它打算在再次处理任务之前休眠5秒：

def main():
    sql = 'some sql task here;'
    stop_time = datetime.today() + timedelta(minutes = 20)
    print('Started at ', datetime.now())
    print('Should stop at', stop_time)
    load_more_rows = True
    with ConnectionParameters.get_conn() as conn:
        while load_more_rows or (datetime.now() < stop_time):
            try:
                res = get_num_processed_batches(conn, sql)
                processed_batch = res > 0
            except Exception as ex:
                log_error(repr(ex))
                processed_batch = False
            if not processed_batch:
                print('Sleeping at ', datetime.now())
                time.sleep(seconds=5)
            load_more_rows = processed_batch
            print('Finished iteration at ', datetime.now())
    print('Stopped at ', datetime.now())

不幸的是，它不是睡觉、醒来和继续处理任务直到时间结束，而是完全停止执行，如输出所示：

('Started at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 206652))
('Should stop at', datetime.datetime(2015, 3, 31, 17, 51, 6, 206630))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 356698))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 614349))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 638210))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 765645))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 6, 885282))
('Finished iteration at ', datetime.datetime(2015, 3, 31, 17, 31, 7, 12109))
('Sleeping at ', datetime.datetime(2015, 3, 31, 17, 31, 7, 13803))

我做错了什么？

Answer 1

time.sleep不使用关键字参数seconds

time.sleep(5)

我不知道为什么它不会引起一个错误，因为缺少一个必要的参数。

https://docs.python.org/2/library/time.html#time.sleep

>>> time.sleep(seconds=1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: sleep() takes no keyword arguments
>>> time.sleep(1)
>>> "everything is fine"