Apache Kafka Kafka Producers & Consumers 3

Question 1

What is a 'consumer lag' in Kafka?

Accepted Answer

The difference between the latest produced offset and the consumer's current offset

Answer

Network delay between consumer and broker

Answer

Time to deserialize a message

Answer

Gap between two consumer group versions

Question 2

What does the `fetch.min.bytes` consumer configuration control?

Accepted Answer

Minimum data the broker returns in a fetch response before sending

Answer

Minimum message size accepted

Answer

Lowest batch byte threshold for compression

Answer

Minimum bytes written before a commit

Question 3

Which of the following accurately describes a 'sticky partitioner' for producers?

Accepted Answer

It sends all batched messages to the same partition until the batch is full or linger.ms expires

Answer

It always routes by message key hash

Answer

It round-robins by broker ID

Answer

It assigns partitions based on consumer group membership

Question 4

When using `assign()` instead of `subscribe()`, what is the consumer responsible for?

Accepted Answer

Manually managing partition assignment without group coordinator involvement

Answer

Heartbeating to all brokers

Answer

Committing offsets to ZooKeeper

Answer

Electing the group leader

Question 5

What type of serializer is required when the producer message key is a String?

Accepted Answer

org.apache.kafka.common.serialization.StringSerializer

Answer

ByteArraySerializer

Answer

IntegerSerializer

Answer

JsonSerializer

Question 6

What is the effect of setting `retries=0` on a Kafka producer?

Accepted Answer

The producer will not retry failed sends, potentially losing messages on transient errors

Answer

Messages are retried indefinitely

Answer

The producer switches to synchronous mode

Answer

Acknowledgment is disabled