Confluent Confluent Certifications CCDAK Questions & Answers

• Question 111:

  Your topic is log compacted and you are sending a message with the key K and value null. What will happen?

  A. The broker will delete all messages with the key K upon cleanup

  B. The producer will throw a Runtime exception

  C. The broker will delete the message with the key K and null value only upon cleanup

  D. The message will get ignored by the Kafka broker

  Correct Answer: A

  Sending a message with the null value is called a tombstone in Kafka and will ensure the log compacted topic does not contain any messages with the key K upon compaction

• Question 112:

  Suppose you have 6 brokers and you decide to create a topic with 10 partitions and a replication factor of 3. The brokers 0 and 1 are on rack A, the brokers 2 and 3 are on rack B, and the brokers 4 and 5 are on rack C. If the leader for partition 0 is on broker 4, and the first replica is on broker 2, which broker can host the last replica? (select two)

  A. 6

  B. 1

  C. 2

  D. 5

  E. 0

  F. 3

  Correct Answer: BE

  When you create a new topic, partitions replicas are spreads across racks to maintain availability. Hence, the Rack A, which currently does not hold the topic partition, will be selected for the last replica

• Question 113:

  The kafka-console-consumer CLI, when used with the default options

  A. uses a random group id

  B. always uses the same group id

  C. does not use a group id

  Correct Answer: C

• Question 114:

  A producer is sending messages with null key to a topic with 6 partitions using the DefaultPartitioner. Where will the messages be stored?

  A. Partition 5

  B. Any of the topic partitions

  C. The partition for the null key

  D. Partition 0

  Correct Answer: B

• Question 115:

  Which of the following Kafka Streams operators are stateless? (select all that apply)

  A. map

  B. filter

  C. flatmap

  D. branch

  E. groupBy

  F. aggregate

  Correct Answer: ABCDE

  Seehttps://kafka.apache.org/20/documentation/streams/developer-guide/dsl- api.html#stateless-transformations

• Question 116:

  How will you read all the messages from a topic in your KSQL query?

  A. KSQL reads from the beginning of a topic, by default.

  B. KSQL reads from the end of a topic. This cannot be changed.

  C. Use KSQL CLI to set auto.offset.reset property to earliest

  Correct Answer: C

  Consumers can set auto.offset.reset property to earliest to start consuming from beginning. For KSQL, SET 'auto.offset.reset'='earliest';

• Question 117:

  If I produce to a topic that does not exist, and the broker setting auto.create.topic.enable=true, what will happen?

  A. Kafka will automatically create the topic with 1 partition and 1 replication factor

  B. Kafka will automatically create the topic with the indicated producer settings num.partitions and default.replication.factor

  C. Kafka will automatically create the topic with the broker settings num.partitions and default.replication.factor

  D. Kafka will automatically create the topic with num.partitions=#of brokers and replication.factor=3

  Correct Answer: C

  The broker settings comes into play when a topic is auto created

• Question 118:

  If I supply the setting compression.type=snappy to my producer, what will happen? (select two)

  A. The Kafka brokers have to de-compress the data

  B. The Kafka brokers have to compress the data

  C. The Consumers have to de-compress the data

  D. The Consumers have to compress the data

  E. The Producers have to compress the data

  Correct Answer: CE

  Kafka transfers data with zero copy and no transformation. Any transformation (including compression) is the responsibility of clients.

• Question 119:

  A client connects to a broker in the cluster and sends a fetch request for a partition in a topic. It gets an exception Not Leader For Partition Exception in the response. How does client handle this situation?

  A. Get the Broker id from Zookeeper that is hosting the leader replica and send request to it

  B. Send metadata request to the same broker for the topic and select the broker hosting the leader replica

  C. Send metadata request to Zookeeper for the topic and select the broker hosting the leader replica

  D. Send fetch request to each Broker in the cluster

  Correct Answer: B

  In case the consumer has the wrong leader of a partition, it will issue a metadata request. The Metadata request can be handled by any node, so clients know afterwards which broker are the designated leader for the topic partitions. Produce and consume requests can only be sent to the node hosting partition leader.

• Question 120:

  A Zookeeper ensemble contains 3 servers. Over which ports the members of the ensemble should be able to communicate in default configuration? (select three)

  A. 2181

  B. 3888

  C. 443

  D. 2888

  E. 9092

  F. 80

  Correct Answer: ABD

  2181 - client port, 2888 - peer port, 3888 - leader port