Consumers & groups — manual commits, at-least-once, no loss across crashes

6 h
requires KFK-02

From your world. SOX completeness: a crash must never drop an unprocessed event

Practice quiz with instant feedback. For a scored run that counts toward your local progress, use uv run de quiz KFK-04.

2A consumer uses enable.auto.commit=true. It polls a batch. Auto-commit runs. Then the process crashes before it finishes the batch. After the restart, what happens to those records? AThey are reprocessed from the start of the batch. BThey are skipped. The offset was already committed, so the group resumes after them (at-most-once). CThey are delivered to a dead-letter topic automatically. DThey are delivered to every consumer in the group.

4What does KIP-848 (the new consumer group protocol in Kafka 4.x) mainly change? AIt removes consumer groups entirely. BIt moves assignment to the broker-side coordinator with incremental reconciliation. This reduces stop-the-world rebalances. CIt makes every consumer read every partition. DIt replaces offsets with timestamps.

7How do share groups (KIP-932) differ from classic consumer groups? AThey guarantee exactly-once by default. BThey allow multiple consumers to share the records of a partition, with per-record acknowledgement (queue-like). Classic groups use one partition for each consumer. CThey remove the need for brokers. DThey work only with transactions.