Confluent CCDAK Exam Questions Instant Access

Question 1

StreamsBuilder builder = new StreamsBuilder();

KStream textLines = builder.stream("word-count-input");

KTable wordCounts = textLines

.mapValues(textLine -> textLine.toLowerCase())

.flatMapValues(textLine -> Arrays.asList(textLine.split("\W+")))

.selectKey((key, word) -> word)

.groupByKey()

.count(Materialized.as("Counts"));

wordCounts.toStream().to("word-count-output", Produced.with(Serdes.String(), Serdes.Long()));

builder.build();

What is an adequate topic configuration for the topic word-count-output?

Amax.message.bytes=10000000

Bcleanup.policy=delete

Ccompression.type=lz4

Dcleanup.policy=compact

Answer : D

Result is aggregated into a table with key as the unique word and value its frequency. We have to enable log compaction for this topic to align the topic's cleanup policy with KTable semantics.

Question 2

We have a store selling shoes. What dataset is a great candidate to be modeled as a KTable in Kafka Streams?

AMoney made until now

BThe transaction stream

CItems returned

DInventory contents right now

Answer : A, C

Aggregations of stream are stored in table, whereas Streams must be modeled as a KStream to avoid data explosion

Question 3

We would like to be in an at-most once consuming scenario. Which offset commit strategy would you recommend?

ACommit the offsets on disk, after processing the data

BDo not commit any offsets and read from beginning

CCommit the offsets in Kafka, after processing the data

DCommit the offsets in Kafka, before processing the data

Answer : D

Here, we must commit the offsets right after receiving a batch from a call to .poll()

Question 4

A consumer starts and has auto.offset.reset=none, and the topic partition currently has data for offsets going from 45 to 2311. The consumer group has committed the offset 10 for the topic before. Where will the consumer read from?

Aoffset 45

Boffset 10

Cit will crash

Doffset 2311

Answer : C

auto.offset.reset=none means that the consumer will crash if the offsets it's recovering from have been deleted from Kafka, which is the case here, as 10 < 45

Question 5

A consumer starts and has auto.offset.reset=latest, and the topic partition currently has data for offsets going from 45 to 2311. The consumer group has committed the offset 643 for the topic before. Where will the consumer read from?

Ait will crash

Boffset 2311

Coffset 643

Doffset 45

Answer : C

The offsets are already committed for this consumer group and topic partition, so the property auto.offset.reset is ignored

Question 6

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

AKSQL reads from the beginning of a topic, by default.

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

CUse KSQL CLI to set auto.offset.reset property to earliest

Answer : C

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

Question 7

Using the Confluent Schema Registry, where are Avro schema stored?

AIn the Schema Registry embedded SQL database

BIn the Zookeeper node /schemas

CIn the message bytes themselves

DIn the _schemas topic

Answer : D

The Schema Registry stores all the schemas in the _schemas Kafka topic

Confluent Certified Developer for Apache Kafka CCDAK Exam Questions