- A
Increase the number of subscriber clients (parallel pull consumers)
More subscribers pull messages concurrently, increasing overall throughput.
- B
Set ordering keys on the subscription
Why wrong: Ordering keys guarantee order but can reduce throughput due to head-of-line blocking.
- C
Use a push subscription instead of pull
Why wrong: Push subscriptions are generally less suitable for high throughput than pull subscriptions.
- D
Increase the max outstanding messages per subscriber client
Allowing more unacknowledged messages per client increases parallelism and throughput.
- E
Use a pull subscription with an asynchronous puller
Asynchronous pulling allows multiple messages to be processed concurrently, improving throughput.
Question 710 of 1,000
PCDE Optimising Service Performance Practice Question
This PCDE practice question tests your understanding of optimising service performance. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
A Cloud Pub/Sub subscription is used to ingest real-time events. The subscriber's processing rate is slower than the publish rate, causing messages to back up. The team needs to increase throughput without losing messages. Which three actions should they take? (Choose three.)
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
✓
Increase the number of subscriber clients (parallel pull consumers)
Increasing the acknowledgement deadline prevents premature redelivery but does not increase throughput. Using flow control (max outstanding messages) can actually reduce throughput. To increase throughput: increase the number of subscriber clients (more parallel pulls), use pull subscriptions (more efficient than push for high volume), and increase the max outstanding messages per client (allows more concurrent processing). Ordering keys are not needed for throughput and can reduce it.
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.
- ✓
Increase the number of subscriber clients (parallel pull consumers)
Why this is correct
More subscribers pull messages concurrently, increasing overall throughput.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Set ordering keys on the subscription
Why it's wrong here
Ordering keys guarantee order but can reduce throughput due to head-of-line blocking.
- ✗
Use a push subscription instead of pull
Why it's wrong here
Push subscriptions are generally less suitable for high throughput than pull subscriptions.
- ✓
Increase the max outstanding messages per subscriber client
Why this is correct
Allowing more unacknowledged messages per client increases parallelism and throughput.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Use a pull subscription with an asynchronous puller
Why this is correct
Asynchronous pulling allows multiple messages to be processed concurrently, improving throughput.
Related concept
Read the scenario before looking for a memorised answer.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which PCDE 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.
- →
Optimising Service Performance — study guide chapter
Learn the concepts, then practise the questions
- →
Optimising Service Performance practice questions
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FAQ
Questions learners often ask
What does this PCDE question test?
Optimising Service Performance — This question tests Optimising Service Performance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the number of subscriber clients (parallel pull consumers) — Increasing the acknowledgement deadline prevents premature redelivery but does not increase throughput. Using flow control (max outstanding messages) can actually reduce throughput. To increase throughput: increase the number of subscriber clients (more parallel pulls), use pull subscriptions (more efficient than push for high volume), and increase the max outstanding messages per client (allows more concurrent processing). Ordering keys are not needed for throughput and can reduce it.
What should I do if I get this PCDE question wrong?
Identify which PCDE 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 PCDE 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 PCDE exam.
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