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Integration / RabbitMQ Interview Questions

What is the difference between publisher confirms and transactions?

Both mechanisms let a producer verify that RabbitMQ actually received a message, but they differ enormously in cost and design.

Publisher ConfirmsTransactions (tx.select)
Asynchronous - broker sends ack/nack per delivery tag without blocking the publisher.Synchronous - publisher calls tx.commit and blocks until the broker responds.
Can batch many outstanding confirms in flight at once.Effectively one round trip per transaction, serializing publishes.
Orders of magnitude higher throughput in practice.Significantly slower under load; largely considered legacy for this reason.

Because of this gap, publisher confirms are the recommended approach for reliable publishing in modern RabbitMQ deployments, and transactions are rarely used outside of legacy code.

Which mechanism is asynchronous and generally higher throughput?
Why are AMQP transactions considered largely legacy today?

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