← PDE·Google Cloud

Question 170 of 499

Building and operationalizing data processing systems →hardMultiple SelectObjective-mapped

Quick Answer

The answer is Cloud Storage for raw data archival and BigQuery for processed analytics data, combined with Cloud Pub/Sub using a dead-letter topic. This trio directly addresses the need for designing reliable streaming data pipelines by separating storage concerns: Cloud Storage provides durable, cost-effective archival for raw sensor data, while BigQuery enables fast, serverless analytics on processed data. The dead-letter topic in Pub/Sub is critical because it captures messages that fail processing, preventing data loss and avoiding backlogs that could degrade the 99.9% uptime SLA. On the Google Professional Data Engineer exam, this scenario tests your understanding of decoupling ingestion from processing and handling failure gracefully—a common trap is choosing a single storage solution like Cloud SQL, which cannot scale for streaming. Remember the memory tip: “Archive raw, analyze processed, dead-letter the failures.”

PDE Practice Question: Building and operationalizing data processing systems

This PDE practice question tests your understanding of building and operationalizing data processing systems. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

Your company is building a data processing system that ingests sensor data from millions of devices, processes it in near real-time to detect anomalies, and stores raw and processed data for long-term analytics. The system must meet a 99.9% uptime SLA and minimize data loss. Which THREE design choices are best? (Choose three.)

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

Question 1hardmulti select

Full question →

A
Use Cloud Pub/Sub as the ingestion layer with a dead-letter topic to capture unprocessed messages.
Dead-letter topics prevent data loss by storing messages that cannot be processed after retries.
B
Store raw data in Cloud Bigtable and processed data in Cloud Storage.
Why wrong: Bigtable is expensive for raw data lake; Cloud Storage is better for raw data and BigQuery for analytics.
C
Use Dataflow with at-least-once processing guarantees and perform deduplication downstream.
At-least-once with dedup meets SLA and avoids data loss; exactly-once may add latency.
D
Use Cloud Storage for raw data archival and BigQuery for processed analytics data.
Cloud Storage is durable and cheap for raw data; BigQuery enables fast analytics with SQL.
E
Use a global Cloud Load Balancer in front of the Dataflow workers.
Why wrong: Dataflow workers are not directly exposed; load balancing is not used for the pipeline itself.

Full breakdown with real-world context →

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

✓

Use Cloud Pub/Sub as the ingestion layer with a dead-letter topic to capture unprocessed messages.

Cloud Pub/Sub with a dead-letter topic ensures that messages that cannot be processed are captured and not lost, directly supporting the requirement to minimize data loss. The dead-letter topic allows for later reprocessing or analysis of failed messages, which is critical for meeting a 99.9% uptime SLA by preventing message backlogs from blocking the ingestion pipeline.

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.

✓
Use Cloud Pub/Sub as the ingestion layer with a dead-letter topic to capture unprocessed messages.
Why this is correct
Dead-letter topics prevent data loss by storing messages that cannot be processed after retries.
Clue confirmation
The clue words "best", "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Store raw data in Cloud Bigtable and processed data in Cloud Storage.
Why it's wrong here
Bigtable is expensive for raw data lake; Cloud Storage is better for raw data and BigQuery for analytics.
✓
Use Dataflow with at-least-once processing guarantees and perform deduplication downstream.
Why this is correct
At-least-once with dedup meets SLA and avoids data loss; exactly-once may add latency.
Clue confirmation
The clue words "best", "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✓
Use Cloud Storage for raw data archival and BigQuery for processed analytics data.
Why this is correct
Cloud Storage is durable and cheap for raw data; BigQuery enables fast analytics with SQL.
Clue confirmation
The clue words "best", "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a global Cloud Load Balancer in front of the Dataflow workers.
Why it's wrong here
Dataflow workers are not directly exposed; load balancing is not used for the pipeline itself.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the misconception that a load balancer is needed to scale Dataflow workers, when in fact Dataflow auto-scales its own workers and uses Pub/Sub's pull subscriptions to distribute messages evenly across workers without a separate load balancer.

Detailed technical explanation

How to think about this question

Pub/Sub's dead-letter topic works by forwarding messages that exceed the maximum number of delivery attempts (configurable up to 100) to a separate topic, where they can be stored indefinitely or replayed. This mechanism is essential for handling transient failures in downstream processing without losing data, and it integrates with Cloud Monitoring to alert on dead-lettered messages. Dataflow's at-least-once processing guarantee is achieved through checkpointing and source-side deduplication, but when combined with a downstream deduplication step (e.g., using Cloud Bigtable row keys or BigQuery's MERGE statement), it provides exactly-once semantics for the overall pipeline.

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.

TExam Day Tips

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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Related PDE practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

Designing data processing systems practice questions

Practise PDE questions linked to Designing data processing systems.

Building and operationalizing data processing systems practice questions

Practise PDE questions linked to Building and operationalizing data processing systems.

Operationalizing machine learning models practice questions

Practise PDE questions linked to Operationalizing machine learning models.

Ensuring solution quality practice questions

Practise PDE questions linked to Ensuring solution quality.

PDE fundamentals practice questions

Practise PDE questions linked to PDE fundamentals.

PDE scenario practice questions

Practise PDE questions linked to PDE scenario.

PDE troubleshooting practice questions

Practise PDE questions linked to PDE troubleshooting.

Practice this exam

Start a free PDE practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

PDE practice-test guide →Study guide →Browse all practice tests

FAQ

Questions learners often ask

What does this PDE question test?

Building and operationalizing data processing systems — This question tests Building and operationalizing data processing systems — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Use Cloud Pub/Sub as the ingestion layer with a dead-letter topic to capture unprocessed messages. — Cloud Pub/Sub with a dead-letter topic ensures that messages that cannot be processed are captured and not lost, directly supporting the requirement to minimize data loss. The dead-letter topic allows for later reprocessing or analysis of failed messages, which is critical for meeting a 99.9% uptime SLA by preventing message backlogs from blocking the ingestion pipeline.

What should I do if I get this PDE question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "best", "minimum / minimize". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

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 →

How Courseiva writes practice questions · Editorial policy

Keep practising

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

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.