ZeroMQ:发送前必须睡觉

Question

我用Forwarder设备写了一个zeromq演示(用pyzmq)

以下是代码(参考https://learning-0mq-with-pyzmq.readthedocs.org/en/latest/pyzmq/devices/forwarder.html):

forwarder.py

import zmq

context = zmq.Context()
frontend = context.socket(zmq.SUB)
frontend.bind('tcp://*:5559')
frontend.setsockopt(zmq.SUBSCRIBE, '')

backend = context.socket(zmq.PUB)
backend.bind('tcp://*:5560')

zmq.device(zmq.FORWARDER, frontend, backend)

sub.py

import zmq

context = zmq.Context()
socket = context.socket(zmq.SUB)
socket.connect('tcp://localhost:5560')
socket.setsockopt(zmq.SUBSCRIBE, '')

while True:
    print socket.recv()

pub.py

import zmq, time

context = zmq.Context()
socket = context.socket(zmq.PUB)
socket.connect('tcp://localhost:5559')
# time.sleep(0.01)
socket.send('9 hahah')

我跑python forwarder.py,python sub.py在终端

然后运行python pub.py,订阅者无法获取消息.但是,如果我在发送之前睡了一点时间(例如0.01秒),它就可以工作了.

所以我的问题是,为什么我sleep之前发送？谢谢.

Answer 1

它被称为慢乔纳综合症.阅读指南,有方法可以使用发布/ 订阅同步来避免它.