- A
Enable message ordering to ensure sequential processing.
Why wrong: Ordering keys can reduce parallelism and lower throughput.
- B
Switch to a pull subscription instead of push.
Why wrong: Pull vs push is not the bottleneck; both can achieve high throughput.
- C
Increase the acknowledgement deadline to 30 seconds.
With 2-second processing time, a 10-second deadline may cause premature redelivery if there is any delay; increasing it reduces redeliveries and improves throughput.
- D
Reduce the flow control max outstanding messages to 100.
Why wrong: Reducing flow control would limit throughput, not increase it.
Question 816 of 1,000
PCDE Optimising Service Performance Practice Question
This PCDE practice question tests your understanding of optimising service performance. 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 Pub/Sub subscription is not keeping up with the message publishing rate. The subscriber is a Cloud Run service that processes each message in about 2 seconds. You have already increased the number of subscribers to 10. What is the next best step to increase throughput?
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 acknowledgement deadline to 30 seconds.
If increasing subscribers does not help, the issue may be the acknowledgement deadline. If the deadline is too short, messages are redelivered before processing completes, causing duplicates and wasted work. Increasing the deadline (from default 10 seconds to something higher like 30 seconds) gives time to process. Flow control limits throughput. Ordering keys can reduce throughput.
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.
- ✗
Enable message ordering to ensure sequential processing.
Why it's wrong here
Ordering keys can reduce parallelism and lower throughput.
- ✗
Switch to a pull subscription instead of push.
Why it's wrong here
Pull vs push is not the bottleneck; both can achieve high throughput.
- ✓
Increase the acknowledgement deadline to 30 seconds.
Why this is correct
With 2-second processing time, a 10-second deadline may cause premature redelivery if there is any delay; increasing it reduces redeliveries and improves throughput.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Reduce the flow control max outstanding messages to 100.
Why it's wrong here
Reducing flow control would limit throughput, not increase it.
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
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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 acknowledgement deadline to 30 seconds. — If increasing subscribers does not help, the issue may be the acknowledgement deadline. If the deadline is too short, messages are redelivered before processing completes, causing duplicates and wasted work. Increasing the deadline (from default 10 seconds to something higher like 30 seconds) gives time to process. Flow control limits throughput. Ordering keys can reduce throughput.
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
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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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