Kafka Topics & Partitions Flashcards

What is the purpose of the replication factor in a Kafka topic?

Answer: It defines how many copies of each partition exist across brokers for fault tolerance

The replication factor specifies how many broker copies exist for each partition, ensuring data durability if a broker fails.

Which Kafka CLI tool is used to create a new topic?

Answer: kafka-topics.sh

kafka-topics.sh with the --create flag is the standard tool for creating new Kafka topics from the command line.

What determines which partition a keyed message is written to?

Answer: hash(key) % number_of_partitions

By default, Kafka uses the murmur2 hash of the key modulo the number of partitions to determine the target partition for a keyed message.

What is the minimum in-sync replicas (min.insync.replicas) setting used for?

Answer: Defines the minimum number of replicas that must acknowledge a write when acks=all

min.insync.replicas specifies how many replicas must be in-sync for a produce request with acks=all to succeed, preventing data loss.

Can you decrease the number of partitions in an existing Kafka topic?

Answer: No, partition count can only be increased, never decreased

Kafka does not support decreasing the partition count of an existing topic because it would require redistributing data and break ordering guarantees.

What is a Kafka topic's 'retention.ms' configuration?

Answer: The time period for which Kafka retains messages before deleting them

retention.ms controls how long Kafka keeps messages in a topic before they are eligible for deletion based on age.