Identifying Slow Queries with Cloud SQL Insights

Your company runs a multi-tier application on Compute Engine with a Cloud SQL backend. Recently, during peak hours, users report slow page loads. Cloud Monitoring shows high CPU on the app servers, but no memory pressure. Cloud Trace shows that the application spends most of its time waiting for database queries. The Cloud SQL instance is a high-memory machine type with 16 vCPUs and 64 GB RAM, but CPU utilization on the database is only 30%. There are no slow query alerts. What is the most likely cause and what should you do?

Quick Answer

The answer is that missing database indexes are the most likely cause, and you should use Cloud SQL Insights to identify slow queries and pinpoint those missing indexes. This is correct because the symptoms—high app server CPU, low database CPU at only 30%, and Cloud Trace showing queries consuming most of the application’s wait time—classically indicate inefficient, full-table scans rather than a resource bottleneck on the database itself. On the Google Professional Cloud Developer exam, this scenario tests your ability to differentiate between application-layer and database-layer performance issues, with a common trap being to scale the database instance when the real fix is query optimization. Cloud SQL Insights specifically surfaces query execution plans and wait events to reveal missing indexes, making it the targeted diagnostic tool. Memory tip: when database CPU is low but app servers are struggling, think “low CPU, high wait—indexes are late.”

⚠ Common exam trap

The PCD exam often tests the misconception that high app server CPU always means the app server is the bottleneck, when in fact the CPU is consumed waiting for slow database queries caused by missing indexes.

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 database lacks indexes. Use Cloud SQL Query Insights to identify missing indexes.

The symptoms—high app server CPU, low database CPU, and queries consuming most of the application’s wait time—point to inefficient queries due to missing indexes. Cloud SQL Query Insights can identify these missing indexes by analyzing query execution plans and wait events. Adding appropriate indexes reduces query execution time, lowering app server CPU usage and resolving the slow page loads. Option A is correct because the database lacks indexes; Query Insights helps find them.

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 database lacks indexes. Use Cloud SQL Query Insights to identify missing indexes.
Why this is correct
Missing indexes force full table scans, causing slow queries. Query Insights can reveal the specific slow queries and suggest indexes.
✗
The application is performing unnecessary queries. Add caching with Memorystore.
Why it's wrong here
Caching could reduce load, but the root cause is likely slow queries due to lack of indexes, not unnecessary queries. Traces show waiting on queries, not redundant ones.
✗
The database connection pool is exhausted. Increase the maximum number of connections.
Why it's wrong here
Connection pool exhaustion would likely cause connection errors, not uniformly slow queries; also, database CPU is low, not a symptom of pool issues.
✗
The Cloud SQL instance is under-provisioned. Upgrade to a larger machine type.
Why it's wrong here
Database CPU is only 30%, indicating it is not compute-bound; upgrading would not address the root cause of slow queries.

Visual reference

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

Same concept, more angles

1 more way this is tested on PCD

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. An application uses Cloud SQL and is experiencing slow query performance. The team wants to monitor query latency and identify slow queries. Which Google Cloud tool should they use?

medium

✓ A.Cloud SQL Insights
B.Cloud Debugger
C.Cloud Monitoring
D.Cloud Trace

Why A: Cloud SQL Insights is the correct tool because it is specifically designed to provide detailed query performance diagnostics for Cloud SQL databases. It captures query latency, execution plans, and wait events, enabling teams to identify and troubleshoot slow queries directly within the Cloud SQL console without additional configuration.

Last reviewed: Jun 25, 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 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.