hardMultiple Choice
Google PCA Practice Question: An e-commerce company uses Cloud SQL for MySQL to…
An e-commerce company uses Cloud SQL for MySQL to handle user sessions. During Black Friday sales, the database experiences high read latency and connection timeouts. The traffic pattern shows 95% read operations and 5% write operations. They need to improve read performance without significant architectural changes. Which action should they take?
⚠ Common exam trap
PCA often tests whether candidates choose the least-disruptive, purpose-built solution — read replicas for read scaling — versus over-engineered migrations (Spanner) or tangential fixes (Proxy, storage increases) that sound plausible but miss the actual bottleneck.
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
✓
Add Cloud SQL read replicas and configure the application to use them for read operations.
Adding Cloud SQL read replicas and routing read traffic to them offloads the primary instance, which is the standard, low-disruption way to scale read-heavy workloads. With 95% reads, this directly addresses the bottleneck without architectural changes. Cloud SQL Proxy, Spanner migration, and storage/machine-type increases do not solve read contention as directly or with as little disruption.
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 Cloud SQL Proxy to reduce connection overhead.
Why it's wrong here
Cloud SQL Proxy encrypts and manages connections to the instance; it does not add read capacity, so the 95% read load still saturates the primary. It tempts because connection timeouts suggest connection handling, and it would be correct if the issue were insecure or unmanaged client connectivity rather than read throughput.
- ✗
Migrate from Cloud SQL to Cloud Spanner for better scalability.
Why it's wrong here
Migrating to Cloud Spanner introduces a horizontally scalable, globally distributed relational database, but this fails to address the scenario’s requirement for improved read performance without significant architectural changes. Spanner demands a complete schema redesign, different client drivers, and a shift from MySQL semantics, incurring major re-engineering. It is tempting because Spanner excels at extreme write scalability and strong consistency across regions, which would be correct for a globally distributed write-heavy workload, not the 95% read-heavy, single-region MySQL session store here.
- ✓
Add Cloud SQL read replicas and configure the application to use them for read operations.
Why this is correct
Read replicas offload the 95% read traffic from the primary instance, cutting read latency and connection timeouts during peak load. Writes still go to the primary, and the application needs no architectural change beyond routing reads to replica endpoints.
- ✗
Enable automatic storage increases and increase the machine type of the primary instance.
Why it's wrong here
Scaling the primary instance and enabling storage auto-growth raises write throughput and capacity, but the 95% read workload still hits the same instance, so read latency and connection timeouts persist. It tempts because vertical scaling is a quick fix for general resource exhaustion, and would be correct if writes or storage were the bottleneck.
Go deeper
Related to this question
Learn chapter
Cloud Storage: Objects and Buckets
Key term
Latency
Latency is the time delay between a request being sent over a network and the response being received, often measured in milliseconds.
Key term
Cloud SQL
Cloud SQL is a fully managed relational database service that lets you set up, maintain, and scale SQL databases (like MySQL, PostgreSQL, and SQL Server) in the cloud without managing the underlying infrastructure.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
This PCA 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 PCA exam.