Synchronous SUBSCRIBE Handling

CybusMQ synchronous SUBSCRIBE handling ensures the cluster is ready before sending SUBACK, preventing message loss during overload scenarios.

CybusMQ processes SUBSCRIBE requests synchronously across the cluster. The broker only sends the SUBACK response when all nodes are ready to route messages to the subscribing client.

How It Works

When a client sends a SUBSCRIBE request, CybusMQ performs the following steps before sending SUBACK:

1. Replicates the subscription data to all cluster nodes.

2. Updates routing tables on all nodes.

This synchronous approach ensures that when a client receives SUBACK, the cluster is ready to deliver messages immediately.

Message Loss Prevention

During overload scenarios, asynchronous subscription processing can cause the first few messages to be lost after SUBACK is sent. CybusMQ's synchronous approach prevents this by ensuring all cluster nodes are ready before confirming the subscription.