- A
Enable automatic storage increase on the primary
Why wrong: Storage increase prevents out-of-space errors but does not improve read performance.
- B
Create cross-region read replicas for geographic load balancing
Why wrong: Cross-region replicas add latency and are for disaster recovery, not reducing read latency for local users.
- C
Create Cloud SQL read replicas in the same region
Read replicas serve read traffic, reducing load on the primary and decreasing read latency.
- D
Implement Memorystore for Redis to cache frequent read results
Caching reduces the number of reads hitting the database, lowering read latency and load on the primary.
- E
Increase the machine type of the primary instance
Why wrong: Scaling the primary does not offload reads; it only increases capacity. Read replicas or caching are more effective.
PCD Practice Question: Design Scalable and Highly Available Cloud Database Solutions
This PCD practice question tests your understanding of design scalable and highly available cloud database solutions. 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 company is migrating a MySQL OLTP database to Cloud SQL. The database has a peak of 10,000 read queries per second (QPS) and 2,000 write QPS. The team wants to reduce read latency and offload read traffic from the primary instance. Which TWO actions should they take? (Choose TWO.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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
Create Cloud SQL read replicas in the same region
Cloud SQL supports read replicas (up to 10) that can serve read traffic, offloading the primary. Cross-region replicas increase latency. Using a Memorystore cache reduces repeated reads. Increasing primary machine type does not offload reads; it just scales the primary. Enabling automatic storage increase is for storage, not read performance.
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 automatic storage increase on the primary
Why it's wrong here
Storage increase prevents out-of-space errors but does not improve read performance.
- ✗
Create cross-region read replicas for geographic load balancing
Why it's wrong here
Cross-region replicas add latency and are for disaster recovery, not reducing read latency for local users.
- ✓
Create Cloud SQL read replicas in the same region
Why this is correct
Read replicas serve read traffic, reducing load on the primary and decreasing read latency.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Implement Memorystore for Redis to cache frequent read results
Why this is correct
Caching reduces the number of reads hitting the database, lowering read latency and load on the primary.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Increase the machine type of the primary instance
Why it's wrong here
Scaling the primary does not offload reads; it only increases capacity. Read replicas or caching are more effective.
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 PCD 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.
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FAQ
Questions learners often ask
What does this PCD question test?
Design Scalable and Highly Available Cloud Database Solutions — This question tests Design Scalable and Highly Available Cloud Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create Cloud SQL read replicas in the same region — Cloud SQL supports read replicas (up to 10) that can serve read traffic, offloading the primary. Cross-region replicas increase latency. Using a Memorystore cache reduces repeated reads. Increasing primary machine type does not offload reads; it just scales the primary. Enabling automatic storage increase is for storage, not read performance.
What should I do if I get this PCD question wrong?
Identify which PCD 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.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 →
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Last reviewed: Jul 4, 2026
This PCD 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 PCD exam.
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