SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company runs a critical database on an RDS for MySQL Multi-AZ DB instance. The database is experiencing high read latency. The application is read-heavy and uses many complex joins. The company needs to improve read performance with minimal application changes. Which solution is MOST appropriate?
⚠ Common exam trap
SAP-C02 often tests whether candidates over-engineer with caching or NoSQL when a simpler managed feature (read replicas) solves the problem — the trap is picking ElastiCache or DynamoDB because they sound more 'scalable' despite requiring significant application changes.
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
✓
Create one or more RDS read replicas and direct read queries to the replica endpoint.
RDS read replicas offload read traffic from the primary instance by asynchronously replicating data, and the application only needs to change its read connection string to point at the replica endpoint — a minimal-change solution. This directly addresses read-heavy workloads with complex joins because the replica runs the same MySQL engine and can execute the same queries. It also preserves the existing Multi-AZ failover posture for the primary.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Migrate the database to Amazon DynamoDB Global Tables.
Why it's wrong here
DynamoDB Global Tables require a non-relational data model, so the existing MySQL schema and complex joins cannot run unchanged — this fails the minimal-change requirement. It is tempting because Global Tables deliver multi-Region active-active replication for key-value workloads, and would suit a scenario demanding low-latency global access to denormalised data.
- ✓
Create one or more RDS read replicas and direct read queries to the replica endpoint.
Why this is correct
Read replicas offload read traffic from the primary via MySQL's asynchronous replication, and the application only needs its read connection string repointed to the replica endpoint. This satisfies the minimal-application-change constraint while relieving the primary of complex join reads.
- ✗
Implement Amazon ElastiCache in front of the database to cache query results.
Why it's wrong here
ElastiCache caches identical repeated query results, but complex joins with varied predicates produce low cache hit rates and stale data risks. It is correct when the same read queries recur frequently and tolerate eventual consistency.
- ✗
Increase the DB instance class to a larger size with more vCPUs.
Why it's wrong here
A larger instance class raises CPU and memory but does not add read replicas, so the read-heavy join workload still funnels through one primary endpoint. Vertical scaling is the right choice when a single write-heavy instance is CPU-bound rather than read-bound.
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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 Amazon Web Services exam blueprint
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services 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 SAP-C02 exam.