Pyzmq multipart atomicity issue

atomicity_issue_pull.py

import os
from time import monotonic

import zmq

# Set up a PULL socket
ctx = zmq.Context()
sock  = ctx.socket(zmq.PULL)
sock.set_hwm(1)
sock.connect("tcp://127.0.0.1:8541")

# Receive just before exiting
t0 = monotonic()
msg = sock.recv_multipart()
td = monotonic() - t0
print("Received", len(msg), "parts in", td, "seconds")

atomicity_issue_push.py

from itertools import count

import zmq

# Set up a PUSH socket
ctx = zmq.Context()
sock  = ctx.socket(zmq.PUSH)
sock.set_hwm(1)
sock.bind("tcp://127.0.0.1:8541")

# Send multipart messages containing 512 MB data
data = b'a' * 512 * 1024 * 1024
try:
    for i in count():
        sock.send_multipart([str(i).encode(), data])
        print('sent', i)
except KeyboardInterrupt:
    pass