- A
Memory usage is 50% of 32 GB.
Why wrong: Memory usage at 50% is fine; not a scaling trigger.
- B
CPU utilization consistently above 80%.
High CPU indicates need for more vCPUs.
- C
Disk IOPS is consistently reaching the instance's I/O limit.
Reaching I/O limit requires a larger tier with more IOPS.
- D
Average query latency of 5 ms.
Why wrong: 5 ms is acceptable; not a trigger for scaling.
- E
Network traffic is 100 Mbps.
Why wrong: Network is usually not a bottleneck for Cloud SQL.
Question 39 of 1,000
PCDOE Design and Plan Database Solutions Practice Question
This PCDOE practice question tests your understanding of design and plan 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.
An online payment processing system uses Cloud SQL for MySQL with a 1 TB database. The system experiences high write throughput (~5000 writes/sec) and needs sub-10ms latency. The current instance has 8 vCPUs and 32 GB RAM. Which two metrics would indicate that the instance needs a larger tier? (Choose TWO.)
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
✓
CPU utilization consistently above 80%.
Option B is correct because sustained CPU utilization above 80% indicates the instance is compute-bound, which can lead to queuing and increased latency for write operations. In Cloud SQL for MySQL, high CPU usage often means the instance lacks sufficient vCPUs to handle the write throughput, necessitating a larger tier with more CPU cores.
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.
- ✗
Memory usage is 50% of 32 GB.
Why it's wrong here
Memory usage at 50% is fine; not a scaling trigger.
- ✓
CPU utilization consistently above 80%.
Why this is correct
High CPU indicates need for more vCPUs.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Disk IOPS is consistently reaching the instance's I/O limit.
Why this is correct
Reaching I/O limit requires a larger tier with more IOPS.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Average query latency of 5 ms.
Why it's wrong here
5 ms is acceptable; not a trigger for scaling.
- ✗
Network traffic is 100 Mbps.
Why it's wrong here
Network is usually not a bottleneck for Cloud SQL.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that high memory usage or low latency alone indicates a need for a larger tier, but the key metrics are CPU saturation and I/O limit exhaustion, which directly impact write throughput and latency.
Detailed technical explanation
How to think about this question
Cloud SQL for MySQL instances have predefined IOPS limits tied to the tier (e.g., 1,000 IOPS per vCPU for SSD). Consistently reaching the I/O limit (Option C) causes write operations to queue, increasing latency beyond 10ms. Under the hood, MySQL uses the InnoDB storage engine, where write-heavy workloads can saturate the redo log and doublewrite buffer, making I/O a critical bottleneck. In real-world scenarios, a 5000 writes/sec workload on a 1 TB database often requires at least 16 vCPUs and 64 GB RAM to maintain sub-10ms latency.
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.
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FAQ
Questions learners often ask
What does this PCDOE question test?
Design and Plan Database Solutions — This question tests Design and Plan Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: CPU utilization consistently above 80%. — Option B is correct because sustained CPU utilization above 80% indicates the instance is compute-bound, which can lead to queuing and increased latency for write operations. In Cloud SQL for MySQL, high CPU usage often means the instance lacks sufficient vCPUs to handle the write throughput, necessitating a larger tier with more CPU cores.
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.
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 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.
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