Why delivery guarantees affect correctness in Kafka - Quick Recap

Recall & Review

beginner

What are the three main delivery guarantees in Kafka?

The three main delivery guarantees are:<br>1. At most once<br>2. At least once<br>3. Exactly once

beginner

How does 'at most once' delivery affect message processing correctness?

'At most once' means messages may be lost but never duplicated. This can cause missing data, affecting correctness if all messages are needed.

intermediate

Why can 'at least once' delivery lead to duplicate messages?

'At least once' retries sending messages until acknowledged, which can cause duplicates if acknowledgments are lost or delayed.

intermediate

What makes 'exactly once' delivery important for correctness?

'Exactly once' ensures each message is processed one time only, preventing duplicates and losses, which is critical for accurate results.

advanced

How do delivery guarantees relate to system design choices?

Choosing a delivery guarantee affects complexity, performance, and correctness. For example, 'exactly once' needs more coordination but ensures accuracy.

Which Kafka delivery guarantee can cause message loss but no duplicates?

A At most once

B At least once

C Exactly once

D None of the above

'At most once' may lose messages but never duplicates them.

What is a risk of using 'at least once' delivery?

A Message loss

B Slower processing

C No message delivery

D Message duplication

'At least once' can cause duplicates due to retries.

Which delivery guarantee ensures no duplicates and no message loss?

A Exactly once

B At least once

C At most once

D Best effort

'Exactly once' guarantees single processing of each message.

Why might 'exactly once' delivery be more complex to implement?

A It ignores message order

B It requires no coordination

C It needs extra coordination and state tracking

D It drops messages intentionally

'Exactly once' needs coordination to avoid duplicates and losses.

If correctness means no missing or duplicate data, which guarantee is best?

A At most once

B Exactly once

C None

D At least once

'Exactly once' ensures correctness by preventing loss and duplication.

Explain how each Kafka delivery guarantee affects the correctness of message processing.

Think about message loss and duplication for each guarantee.

Describe why choosing a delivery guarantee impacts system design and correctness.

Consider how guarantees affect reliability and system resources.