👀 Views: 48 💬 Answers: 1 📅 Created: 2025-06-22

python-2.7 multiprocessing queue performance Python

I've been banging my head against this for hours. I'm working with a frustrating scenario with the `multiprocessing` module in Python 2.7, specifically related to `Queue`. I have a producer process that puts messages onto a `Queue`, and multiple consumer processes that consume these messages. However, sometimes it seems like messages are being lost, especially under high load. I have set up my processes as follows: ```python import multiprocessing import time def producer(queue): for i in range(100): queue.put(i) print('Produced:', i) time.sleep(0.01) # Simulate work def consumer(queue): while True: item = queue.get() if item is None: break # Exit signal print('Consumed:', item) if __name__ == '__main__': queue = multiprocessing.Queue() proc_producer = multiprocessing.Process(target=producer, args=(queue,)) proc_consumer1 = multiprocessing.Process(target=consumer, args=(queue,)) proc_consumer2 = multiprocessing.Process(target=consumer, args=(queue,)) proc_producer.start() proc_consumer1.start() proc_consumer2.start() proc_producer.join() queue.put(None) # Signal consumers to exit proc_consumer1.join() proc_consumer2.join() ``` I've noticed that when I increase the sleep time in the producer or the number of consumer processes, the question seems to get worse. Sometimes, the consumer processes report that they have consumed fewer messages than the producer claims to have produced, which is concerning. I've also tried using a `JoinableQueue`, but that hasn't resolved the scenario either. Is there something specific to how `multiprocessing.Queue` handles message passing that I might be overlooking? Any suggestions on best practices to ensure that messages are reliably passed from producer to consumer in Python 2.7? Am I approaching this the right way?