← PCDOE·Google Cloud

Question 36 of 500

Optimizing service performance →hardMultiple ChoiceObjective-mapped

PCDOE Optimizing service performance Practice Question

This PCDOE practice question tests your understanding of optimizing 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.

Exhibit

httpRequest: {
  requestMethod: "POST"
  requestUrl: "https://example.com/api/orders"
  status: 200
  responseSize: "4521"
  latency: "2.345s"
  remoteIp: "203.0.113.100"
  cacheHit: false
}
httpRequest: {
  requestMethod: "POST"
  requestUrl: "https://example.com/api/orders"
  status: 200
  responseSize: "4521"
  latency: "0.012s"
  remoteIp: "203.0.113.101"
  cacheHit: true
}

Refer to the exhibit. The team observes that some requests are fast while others are slow. Both requests have identical payload and response. What is the most likely cause of the latency difference?

Clue words in this question

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

Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Question 1hardmultiple choice

Full question →

Exhibit

httpRequest: {
  requestMethod: "POST"
  requestUrl: "https://example.com/api/orders"
  status: 200
  responseSize: "4521"
  latency: "2.345s"
  remoteIp: "203.0.113.100"
  cacheHit: false
}
httpRequest: {
  requestMethod: "POST"
  requestUrl: "https://example.com/api/orders"
  status: 200
  responseSize: "4521"
  latency: "0.012s"
  remoteIp: "203.0.113.101"
  cacheHit: true
}

A
The fast request hit a cached response
The cacheHit field shows true for the fast request, indicating a cache hit reduced latency.
B
The slow request had a larger response size
Why wrong: Both responses have the same size (4521).
C
The fast request used a different load balancer
Why wrong: There is no indication of different load balancers; the logs are from the same load balancer.
D
The slow request used a different HTTP method
Why wrong: Both requests use POST, same method.

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

✓

The fast request hit a cached response

The fast request hit a cached response, meaning the reverse proxy or CDN served the response from its cache without forwarding the request to the origin server. This eliminates the round-trip time to the backend and the processing time on the origin, resulting in significantly lower latency. Since both requests have identical payloads and responses, caching is the most plausible explanation for the observed difference.

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.

✓
The fast request hit a cached response
Why this is correct
The cacheHit field shows true for the fast request, indicating a cache hit reduced latency.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The slow request had a larger response size
Why it's wrong here
Both responses have the same size (4521).
✗
The fast request used a different load balancer
Why it's wrong here
There is no indication of different load balancers; the logs are from the same load balancer.
✗
The slow request used a different HTTP method
Why it's wrong here
Both requests use POST, same method.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the misconception that latency differences must be caused by network or server-side factors, when in fact caching is the most common and simplest explanation for identical requests with different response times.

Detailed technical explanation

How to think about this question

HTTP caching relies on headers like Cache-Control (e.g., max-age, s-maxage) and ETag to determine freshness. A reverse proxy such as Nginx or Varnish can serve cached responses directly from memory (RAM), bypassing the entire backend stack. In real-world scenarios, cache hit ratios are critical for performance; a single cache miss can add 100–500 ms of backend processing time, while a cache hit often completes in under 10 ms.

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

Related PCDOE practice-question pages

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

Bootstrapping a Google Cloud organization for DevOps practice questions

Practise PCDOE questions linked to Bootstrapping a Google Cloud organization for DevOps.

Managing service incidents practice questions

Practise PCDOE questions linked to Managing service incidents.

Managing Google Cloud costs practice questions

Practise PCDOE questions linked to Managing Google Cloud costs.

Building and implementing CI/CD pipelines practice questions

Practise PCDOE questions linked to Building and implementing CI/CD pipelines.

Implementing service monitoring strategies practice questions

Practise PCDOE questions linked to Implementing service monitoring strategies.

Optimizing service performance practice questions

Practise PCDOE questions linked to Optimizing service performance.

PCDOE fundamentals practice questions

Practise PCDOE questions linked to PCDOE fundamentals.

PCDOE scenario practice questions

Practise PCDOE questions linked to PCDOE scenario.

PCDOE troubleshooting practice questions

Practise PCDOE questions linked to PCDOE troubleshooting.

Practice this exam

Start a free PCDOE 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

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

FAQ

Questions learners often ask

What does this PCDOE question test?

Optimizing service performance — This question tests Optimizing service performance — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The fast request hit a cached response — The fast request hit a cached response, meaning the reverse proxy or CDN served the response from its cache without forwarding the request to the origin server. This eliminates the round-trip time to the backend and the processing time on the origin, resulting in significantly lower latency. Since both requests have identical payloads and responses, caching is the most plausible explanation for the observed difference.

What should I do if I get this PCDOE 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

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

Last reviewed: Jun 30, 2026

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 PCDOE 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 PCDOE exam.