GCP Pub/Sub message delivery delays when using Python client with asyncio
I've spent hours debugging this and I've tried everything I can think of but I'm converting an old project and I've looked through the documentation and I'm still confused about I'm experiencing significant delays in message delivery when using the Python client library for Google Cloud Pub/Sub with asyncio... After deploying my application, I noticed that messages published to the topic often take several seconds to reach the subscriber, which is unacceptable for my use case that requires low-latency processing. Here is a simplified version of my publishing code: ```python import asyncio from google.cloud import pubsub_v1 async def publish_messages(project_id, topic_id, messages): publisher = pubsub_v1.PublisherClient() topic_path = publisher.topic_path(project_id, topic_id) for message in messages: future = publisher.publish(topic_path, data=message.encode('utf-8')) print(f'Published {message} with ID {future.result()}') async def main(): messages = ['msg1', 'msg2', 'msg3'] await publish_messages('my-project-id', 'my-topic-id', messages) asyncio.run(main()) ``` In my subscriber code, I'm using the `asyncio` event loop as well: ```python from google.cloud import pubsub_v1 async def callback(message): print(f'Received message: {message.data}') message.ack() async def listen_for_messages(project_id, subscription_id): subscriber = pubsub_v1.SubscriberClient() subscription_path = subscriber.subscription_path(project_id, subscription_id) streaming_pull_future = subscriber.subscribe(subscription_path, callback=callback) print(f'Listening for messages on {subscription_path}...') try: await streaming_pull_future except Exception as e: print(f'Error: {e}') async def main(): await listen_for_messages('my-project-id', 'my-subscription-id') asyncio.run(main()) ``` I've already tried increasing the acknowledgment deadline on the subscriber side and using the `flow_control` parameter while creating the subscriber client, but it hasn't improved the latency. Additionally, I've ensured that both the publisher and subscriber are located in the same region to minimize network latency. Could anyone advise if there are specific best practices or configurations that I might be missing to improve the message delivery speed? Any insights into handling asyncio with GCP Pub/Sub effectively would be very helpful! This is part of a larger CLI tool I'm building. Is there a better approach? My development environment is Ubuntu 22.04. I'm developing on Ubuntu 20.04 with Python.