- A
Pub/Sub with exactly-once delivery enabled
Pub/Sub offers exactly-once delivery for pull subscriptions when enabled.
- B
Dataproc with checkpointing
Why wrong: Checkpointing provides fault tolerance but not exactly-once processing guarantees.
- C
Dataflow with exactly-once processing mode
Dataflow's exactly-once mode ensures each record is processed exactly once, even in failure scenarios.
- D
Pub/Sub Lite with at-least-once delivery
Why wrong: Pub/Sub Lite only offers at-least-once delivery.
- E
Cloud Storage with object versioning
Why wrong: Versioning preserves history but does not guarantee exactly-once processing.
Question 125 of 1,000
PDE Designing Data Processing Systems Practice Question
This PDE practice question tests your understanding of designing data processing systems. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
You are designing a data pipeline for a financial services company that requires exactly-once processing semantics. Which TWO services or configurations provide exactly-once guarantees?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Pub/Sub with exactly-once delivery enabled
Pub/Sub with exactly-once delivery enabled provides exactly-once message delivery. Dataflow with exactly-once processing mode ensures each record is processed exactly once. Pub/Sub Lite and Dataproc do not provide exactly-once guarantees, and Cloud Storage is for storage.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Pub/Sub with exactly-once delivery enabled
Why this is correct
Pub/Sub offers exactly-once delivery for pull subscriptions when enabled.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Dataproc with checkpointing
Why it's wrong here
Checkpointing provides fault tolerance but not exactly-once processing guarantees.
- ✓
Dataflow with exactly-once processing mode
Why this is correct
Dataflow's exactly-once mode ensures each record is processed exactly once, even in failure scenarios.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Pub/Sub Lite with at-least-once delivery
Why it's wrong here
Pub/Sub Lite only offers at-least-once delivery.
- ✗
Cloud Storage with object versioning
Why it's wrong here
Versioning preserves history but does not guarantee exactly-once processing.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which PDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
- →
Designing Data Processing Systems — study guide chapter
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FAQ
Questions learners often ask
What does this PDE question test?
Designing Data Processing Systems — This question tests Designing Data Processing Systems — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Pub/Sub with exactly-once delivery enabled — Pub/Sub with exactly-once delivery enabled provides exactly-once message delivery. Dataflow with exactly-once processing mode ensures each record is processed exactly once. Pub/Sub Lite and Dataproc do not provide exactly-once guarantees, and Cloud Storage is for storage.
What should I do if I get this PDE question wrong?
Identify which PDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This PDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PDE exam.
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