What overhead does Kafka have for idempotent sending? What does Kafka sacrifice in this case?

Idempotent sending in Kafka is achieved through unique message identifiers and sequence number control on the producer side. This prevents message duplication during retries.

The overhead includes:

• Additional storage and management of producer state to track sequence numbers.
• Increased load on brokers for checking and confirming message uniqueness.
• Possible reduction in throughput due to synchronization and acknowledgments.

Ultimately, Kafka sacrifices some performance and increases latency to guarantee idempotency and prevent message duplication.