SAA-C03 Design High-Performing Architectures Practice Question
Exhibit
Amazon RDS for PostgreSQL metrics during the end-of-day report window: - CPUUtilization: 24% - ReadLatency: 118 ms - WriteLatency: 7 ms - DiskQueueDepth: 0.4 - FreeStorageSpace: stable Application notes: - Report queries are read-only and run for 20 to 30 minutes - The operational API continues to perform writes during the report window - Business accepts slightly stale report data if write performance stays unchanged
Based on the exhibit, what is the best change to improve read performance without increasing write latency on the primary database?
⚠ Common exam trap
Many candidates confuse Multi-AZ (which only provides failover redundancy) with read replicas (which provide read scaling), leading candidates to incorrectly select Multi-AZ as a performance solution.
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 an RDS read replica and direct the reporting queries to the replica endpoint.
Creating an RDS read replica offloads read-heavy reporting queries from the primary database instance, improving read performance without increasing write latency on the primary. The replica operates asynchronously, so writes on the primary are not blocked or delayed by the reporting workload.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create an RDS read replica and direct the reporting queries to the replica endpoint.
Why this is correct
A read replica offloads the long-running read-only reports from the primary database, which preserves write performance and reduces read latency for the reporting workload. Because the business accepts slightly stale report data, the asynchronous replication delay is acceptable. This is the most direct and AWS-native way to separate read pressure from writes.
- ✗
Convert the DB instance to Multi-AZ so the primary can serve more reads.
Why it's wrong here
Multi-AZ deployments synchronously replicate to a standby in a different Availability Zone for high availability and automatic failover, but that standby is not accessible for reads; it is a passive replica. Therefore, converting to Multi-AZ does not add any additional read capacity or offload the reporting workload from the primary, so long-running reports would continue to compete with production writes for the same underlying instance resources.
When this WOULD be correct
If the question asked for the best change to improve database availability and minimize downtime during a planned maintenance or failure, Multi-AZ would be correct. For example: 'What change provides automatic failover in case of an AZ outage?'
- ✗
Increase the primary instance class to a larger size and keep all traffic on one writer.
Why it's wrong here
Scaling up the primary DB instance provides more CPU, memory, and I/O capacity, but all read and write traffic still traverses the same engine and connection pool, so long-running reporting queries will continue to impact write latency and consume shared resources. This is a temporary or capacity-band-aid solution, not a scalable separation of concerns, and it does not inherently prioritize or isolate reporting traffic. Horizontal read scaling via a dedicated read endpoint is the more durable approach.
When this WOULD be correct
If the question asked for the best way to improve overall database performance for both reads and writes without adding a read replica or changing architecture, scaling up the instance class would be correct.
- ✗
Migrate the reporting workload to DynamoDB to gain faster reads.
Why it's wrong here
DynamoDB is a NoSQL key-value store that offers fast point lookups and horizontal scaling, but migrating a relational reporting workload requires fully rearchitecting the schema, rewriting queries, and reimplementing joins, aggregations, and transactional consistency. This would be a major engineering effort with significant risk, whereas the problem is simply that read-heavy reporting queries are competing with writes on the existing RDS instance. The correct fix should isolate the load without a costly data model migration.
When this WOULD be correct
This option would be correct if the question asked for a fully managed NoSQL solution to handle high-scale, low-latency reads for a new application with flexible schema requirements, and the existing relational database is not suitable for the workload.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SAA-C03 exam frequently reuses these exact scenarios with slightly different constraints.
✓Create an RDS read replica and direct the reporting queries to the replica endpoint.Correct answer▾
Why this is correct
A read replica offloads the long-running read-only reports from the primary database, which preserves write performance and reduces read latency for the reporting workload. Because the business accepts slightly stale report data, the asynchronous replication delay is acceptable. This is the most direct and AWS-native way to separate read pressure from writes.
✗Convert the DB instance to Multi-AZ so the primary can serve more reads.Wrong answer — click to see why▾
Why this is wrong here
Multi-AZ is designed for high availability and failover, not for read scaling. It does not serve reads from the standby; the standby is only used for failover, so it does not improve read performance.
★ When this WOULD be the correct answer
If the question asked for the best change to improve database availability and minimize downtime during a planned maintenance or failure, Multi-AZ would be correct. For example: 'What change provides automatic failover in case of an AZ outage?'
Why candidates choose this
Candidates may mistakenly think Multi-AZ provides read scaling because it involves a second instance, confusing it with read replicas.
✗Increase the primary instance class to a larger size and keep all traffic on one writer.Wrong answer — click to see why▾
Why this is wrong here
Increasing the primary instance class improves overall performance but does not specifically improve read performance without increasing write latency; it also increases cost and does not offload read traffic from the primary.
★ When this WOULD be the correct answer
If the question asked for the best way to improve overall database performance for both reads and writes without adding a read replica or changing architecture, scaling up the instance class would be correct.
Why candidates choose this
Candidates may think that a larger instance handles more reads inherently, overlooking that read replicas offload reads without affecting write latency.
✗Migrate the reporting workload to DynamoDB to gain faster reads.Wrong answer — click to see why▾
Why this is wrong here
Migrating to DynamoDB would require re-architecting the application and data model, which is not a simple change to improve read performance on an existing RDS primary database. It also does not address the goal of not increasing write latency on the primary, as DynamoDB is a different database service.
★ When this WOULD be the correct answer
This option would be correct if the question asked for a fully managed NoSQL solution to handle high-scale, low-latency reads for a new application with flexible schema requirements, and the existing relational database is not suitable for the workload.
Why candidates choose this
Candidates may think DynamoDB offers faster reads due to its managed nature and low-latency performance, but they overlook the significant migration effort and the fact that the question specifically targets improving read performance on the existing primary database without increasing write latency.
Analysis generated from the official SAA-C03blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
About these practice questions
This SAA-C03 question is part of Courseiva's 935-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAA-C03 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 SAA-C03 exam.