Deduplication in Distributed Systems: Myths, Realities, and Practical Solutions

Duplication in distributed systems is a common issue due to retries, processing failures, and fault tolerance mechanisms. Deduplication aims to identify and eliminate duplicate messages, but it comes with challenges that impact scalability, performance, and reliability. The post explores how deduplication is implemented in technologies like Kafka and RabbitMQ, and discusses the trade-offs and complexities involved. It also highlights the concept of exactly-once processing as a more realistic goal than exactly-once delivery, emphasizing patterns like idempotency and transactional outboxes to achieve robust message handling.