The correct answer is to implement both an Amazon RDS Read Replica and an Amazon ElastiCache for Redis cluster. An RDS Read Replica directly offloads read-heavy MySQL traffic by creating a read-only copy of the database, which reduces the load on the primary instance and scales read throughput horizontally. ElastiCache complements this by caching the results of frequent queries in memory, drastically reducing the number of database reads for repeated requests and lowering latency. On the AWS Certified Solutions Architect Professional SAP-C02 exam, this scenario tests your ability to distinguish between scaling reads at the database layer versus the application cache layer—a common trap is choosing only one solution when the question explicitly asks for two actions. Remember that read replicas handle raw query volume, while caching handles query repetition; together they form a layered read optimization strategy. A useful memory tip is "Replicas for volume, cache for speed."
SAP-C02 Continuous Improvement for Existing Solutions Practice Question
This SAP-C02 practice question tests your understanding of continuous improvement for existing 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 running a web application on EC2 instances in an Auto Scaling group behind an ALB. The application uses an Amazon RDS for MySQL database. Recently, the application has become slow, and the operations team identifies that the database is the bottleneck due to a high number of read queries. Which TWO actions should a solutions architect take to improve read performance? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add an Amazon RDS Read Replica in the same AWS Region.
Option D is correct because adding an Amazon RDS Read Replica offloads read traffic from the primary MySQL database, allowing read queries to be served by the replica and reducing load on the source instance. This directly addresses the high number of read queries causing the bottleneck, as read replicas are designed for read-heavy workloads and can be promoted to a standalone instance if needed.
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 Multi-AZ for the RDS instance.
Why it's wrong here
Multi-AZ provides failover, not read scaling.
✗
Implement DynamoDB Accelerator (DAX) in front of the database.
Why it's wrong here
DAX is for DynamoDB, not RDS for MySQL.
✗
Scale up the RDS instance to a larger instance type.
Why it's wrong here
Scaling up helps but does not fully address read-heavy workload.
✓
Add an Amazon RDS Read Replica in the same AWS Region.
Why this is correct
Read Replicas can handle read queries, reducing load on the primary.
Related concept
Read the scenario before looking for a memorised answer.
✓
Implement an Amazon ElastiCache for Redis cluster to cache frequent queries.
Why this is correct
Caching reduces database read load.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Multi-AZ with read replicas, assuming the standby instance can serve reads, when in fact Multi-AZ only provides failover and the standby is not accessible for read operations.
Detailed technical explanation
How to think about this question
Amazon RDS Read Replicas use MySQL’s native asynchronous replication to maintain a consistent copy of the database; read queries can be directed to the replica using a separate endpoint, reducing load on the primary. Amazon ElastiCache for Redis caches the results of frequent read queries in memory, providing sub-millisecond latency and drastically reducing database load, especially for repetitive queries that return the same data. In a real-world scenario, combining read replicas for scaling read capacity and ElastiCache for caching hot data can handle massive read spikes without over-provisioning the primary database.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Continuous Improvement for Existing Solutions — This question tests Continuous Improvement for Existing Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Add an Amazon RDS Read Replica in the same AWS Region. — Option D is correct because adding an Amazon RDS Read Replica offloads read traffic from the primary MySQL database, allowing read queries to be served by the replica and reducing load on the source instance. This directly addresses the high number of read queries causing the bottleneck, as read replicas are designed for read-heavy workloads and can be promoted to a standalone instance if needed.
What should I do if I get this SAP-C02 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.
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Question Discussion
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