- A
Average commit latency
High commit latency can indicate contention, increasing CPU.
- B
Read and write throughput (operations/second)
Throughput directly correlates with CPU usage.
- C
Lock wait time
Why wrong: Lock wait time is a symptom, but often considered part of commit latency.
- D
Stale read rate
Why wrong: Stale reads are a replica metric, not a primary cause of high CPU.
- E
Number of nodes
Why wrong: Node count is a configuration, not a performance metric.
Quick Answer
The answer is read and write throughput (operations/second) and commit latency and lock wait time. These two metrics are the primary indicators because high CPU in Cloud Spanner typically stems from either excessive workload volume or internal contention. Read and write throughput reveals whether the instance is simply being pushed beyond its capacity, while commit latency and lock wait time expose transaction conflicts that force the CPU to waste cycles on retries and coordination. On the Google Professional Cloud Database Engineer exam, this question tests your ability to differentiate between workload-driven and contention-driven performance issues—a common trap is to focus on node count or stale reads, which are configuration or replication metrics, not direct CPU drivers. A useful memory tip is “Throughput for volume, latency for conflict”: if throughput is high, scale nodes; if latency is high, optimize queries or reduce lock contention.
PCDE Monitor and optimize database performance Practice Question
This PCDE practice question tests your understanding of monitor and optimize database performance. Examine the command output carefully: the correct answer depends on what the output actually shows, not on general recall alone. 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.
You are monitoring a Cloud Spanner instance that is experiencing high CPU utilization (consistently above 70%). You want to identify the root cause. Which TWO metrics should you examine first? (Choose two.)
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"first"Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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
Average commit latency
Examining read and write throughput helps identify if the workload is pushing the instance. Analyzing commit latency and lock wait time reveals contention. Stale reads show replica lag but are not primary indicators of high CPU. Node count is configuration, not utilization.
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.
- ✓
Average commit latency
Why this is correct
High commit latency can indicate contention, increasing CPU.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Read and write throughput (operations/second)
Why this is correct
Throughput directly correlates with CPU usage.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Lock wait time
Why it's wrong here
Lock wait time is a symptom, but often considered part of commit latency.
- ✗
Stale read rate
Why it's wrong here
Stale reads are a replica metric, not a primary cause of high CPU.
- ✗
Number of nodes
Why it's wrong here
Node count is a configuration, not a performance metric.
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.
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FAQ
Questions learners often ask
What does this PCDE question test?
Monitor and optimize database performance — This question tests Monitor and optimize database performance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Average commit latency — Examining read and write throughput helps identify if the workload is pushing the instance. Analyzing commit latency and lock wait time reveals contention. Stale reads show replica lag but are not primary indicators of high CPU. Node count is configuration, not utilization.
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.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
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: Jun 24, 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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