CCDAK Sample Questions Answers

Clients with old schema will be able to read records saved with new schema.

KSQL is not ANSI SQL compliant, for now there are no defined standards on streaming SQL languages

linger.ms forces the producer to wait to send messages, hence increasing the chance of creating batches

Clients with new schema will be able to read records saved with old schema.

See https://stackoverflow.com/a/37748336/3019499

Log compaction retains at least the last known value for each record key for a single topic partition. All compacted log offsets remain valid, even if record at offset has been compacted away as a consumer will get the next highest offset.

two partitions groups - one for each application so that all messages are delivered to both the application. 4 consumers in each as there are 4 partitions of the topic, and you cannot have more consumers per groups than the number of partitions (otherwise they will be inactive and wasting resources)

On the producer side, after receiving base64 data, the REST Proxy will convert it into bytes and then send that bytes payload to Kafka. Therefore consumers reading directly from Kafka will receive binary data.

unclean.leader.election.enable=true allows non ISR replicas to become leader, ensuring availability but losing consistency as data loss will occur

Only one of the replicas is elected as partition leader. And a broker can definitely hold many partitions from the same topic on its disk, try creating a topic with 12 partitions on one broker!

This will allow consumers to wait and receive more bytes in each fetch request.

Seehttps://docs.confluent.io/current/streams/developer-guide/dsl-api.html#joining

majority consists of 3 zk nodes for 5 nodes zk cluster, so 2 can fail

ACLs are stored in Zookeeper node /kafka-acls/ by default.

Setting unclean.leader.election.enable to true means we allow out-of-sync replicas to become leaders, we will lose messages when this occurs, effectively losing credit card payments and making our customers very angry.

Consumers do not directly write to the __consumer_offsets topic, they instead interact with a broker that has been elected to manage that topic, which is the Group Coordinator broker

doc represents optional description of message

Partitions for newly created topics are assigned in a rack alternating manner, this is the only change broker.rack does

In Kafka Streams, the application.id is also the underlying group.id for your consumers, and the prefix for all internal topics (repartition and state)