Kafka Producers & Consumers Flashcards

What happens when a consumer's `session.timeout.ms` expires without a heartbeat?

Answer: The consumer is considered dead and a rebalance is triggered

If the broker does not receive a heartbeat from a consumer within session.timeout.ms, it marks that consumer as failed and triggers a group rebalance.

Which producer configuration controls the maximum size of a single request sent to the broker?

Answer: max.request.size

max.request.size limits the size (in bytes) of a request the producer sends to the broker, capping the size of individual produce requests.

What does `auto.offset.reset=earliest` do for a new consumer group?

Answer: Reads from the very beginning of the topic

earliest causes the consumer to start reading from the earliest available offset when no committed offset exists for the group.

How does a Kafka producer achieve idempotency?

Answer: By setting enable.idempotence=true, which assigns a unique producer ID and sequence numbers

Enabling idempotence assigns a Producer ID and per-partition sequence numbers so the broker can deduplicate retried messages.

What is the role of `buffer.memory` in a Kafka producer?

Answer: Total bytes of memory the producer uses to buffer records waiting to be sent

buffer.memory is the total amount of memory the producer allocates for buffering records before they are transmitted to brokers.

Which consumer API call is used to manually commit the current offset synchronously?

Answer: commitSync()

commitSync() blocks until the broker acknowledges the offset commit, providing a reliable but potentially slower commit method.