Exactly-once semantics (EOS) in Kafka - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to enable exactly-once semantics in Kafka producer configuration.

Kafka

Properties props = new Properties();
props.put("enable.idempotence", [1]);

Drag options to blanks, or click blank then click option'

A"maybe"

B"false"

C"yes"

D"true"

Attempts:

3 left

💡 Hint

Common Mistakes

Using false disables idempotence, so exactly-once is not guaranteed.

Using invalid strings causes configuration errors.

Setting enable.idempotence to true enables exactly-once semantics in Kafka producer.

2fill in blank

medium

Complete the code to set the transaction ID for Kafka producer to support EOS.

Kafka

props.put("transactional.id", [1]);

Drag options to blanks, or click blank then click option'

A"txn-123"

Bnull

C""

D123

Attempts:

3 left

💡 Hint

Common Mistakes

Setting transactional.id to null disables transactions.

Using empty string disables transactions.

The transactional.id must be a unique string to enable transactions for exactly-once semantics.

3fill in blank

hard

Fix the error in the code to begin a Kafka transaction correctly.

Kafka

producer.[1]();

Drag options to blanks, or click blank then click option'

AbeginTransaction

BstartTransaction

CinitTransaction

DopenTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Using startTransaction causes a compilation error.

initTransaction and openTransaction do not exist.

The correct method to start a transaction in Kafka producer is beginTransaction().

4fill in blank

hard

Fill both blanks to commit a Kafka transaction and close the producer.

Kafka

producer.[1]();
producer.[2]();

Drag options to blanks, or click blank then click option'

AcommitTransaction

Bclose

Cflush

DabortTransaction

Attempts:

3 left

💡 Hint

Common Mistakes

Calling abortTransaction instead of commitTransaction.

Closing producer before committing transaction.

First commit the transaction with commitTransaction(), then close the producer with close().

5fill in blank

hard

Fill all three blanks to configure Kafka consumer for exactly-once semantics with isolation level and auto commit disabled.

Kafka

props.put("isolation.level", [1]);
props.put("enable.auto.commit", [2]);
props.put("auto.offset.reset", [3]);

Drag options to blanks, or click blank then click option'

A"read_committed"

B"false"

C"earliest"

D"true"

Attempts:

3 left

💡 Hint

Common Mistakes

Setting isolation.level to 'read_uncommitted' breaks EOS.

Enabling auto commit causes duplicate processing.

Using 'latest' for auto.offset.reset may skip messages.

To ensure exactly-once semantics, set isolation.level to read_committed, disable auto commit by setting enable.auto.commit to false, and set auto.offset.reset to earliest to read from the beginning if no offset is found.