The answer is to create one or more RDS read replicas and direct reporting queries to them. This solution offloads reporting queries from the primary PostgreSQL instance, eliminating performance degradation on transactional workloads by routing complex, long-running SELECT statements to a separate read-only copy. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of read replica use cases versus scaling up or switching to Aurora—a common trap is choosing a larger instance size, which helps throughput but doesn’t isolate reporting load and is less cost-effective. Remember that read replicas are ideal for read-heavy workloads like reporting, analytics, or BI, and they can be promoted to primary for disaster recovery. Memory tip: “Replicas for reads, primary for deeds”—keep transactional writes on the primary and offload all reporting reads to replicas.
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 runs a reporting application that queries an Amazon RDS for PostgreSQL database. The queries are complex and take a long time to run, causing performance degradation on the primary instance. The team wants to improve query performance without affecting the transactional workload. Which solution should they use?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 read replicas and direct reporting queries to them
Read replicas offload read queries from the primary. Amazon RDS for PostgreSQL supports read replicas, and the reporting application can be configured to connect to the replica. Option A (increase instance) helps but may not be cost-effective. Option C (Aurora) is an alternative but not necessary. Option D (ElastiCache) is for caching, not complex queries.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Increase the instance size of the primary database
Why it's wrong here
Scaling up helps both workloads but is not the best separation.
✓
Create one or more read replicas and direct reporting queries to them
The clue word "primary" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
✗
Migrate to Amazon RDS for MySQL and use Multi-AZ
Why it's wrong here
Multi-AZ is for high availability, not for offloading read queries.
✗
Use Amazon ElastiCache to cache the results of complex queries
Why it's wrong here
Caching works for repeated queries but not for ad-hoc complex queries.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Create one or more read replicas and direct reporting queries to them — Read replicas offload read queries from the primary. Amazon RDS for PostgreSQL supports read replicas, and the reporting application can be configured to connect to the replica. Option A (increase instance) helps but may not be cost-effective. Option C (Aurora) is an alternative but not necessary. Option D (ElastiCache) is for caching, not complex queries.
What should I do if I get this DBS-C01 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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 →
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. A company uses Amazon RDS for PostgreSQL to run a reporting application. The reporting queries are complex and take several minutes to complete, causing performance impact on the primary instance. The company wants to isolate the reporting workload without data staleness. Which solution should they implement?
medium
A.Implement an Amazon ElastiCache cluster to cache query results.
B.Enable Multi-AZ and use the standby instance for reporting.
C.Take a manual snapshot of the database and restore it for reporting.
✓ D.Create a read replica and direct reporting queries to it.
Why D: Option D is correct because creating a read replica of the Amazon RDS for PostgreSQL primary instance allows you to offload complex reporting queries to the replica without impacting the primary. Read replicas use asynchronous replication (based on PostgreSQL streaming replication), which provides near-real-time data with minimal staleness, satisfying the requirement to isolate the reporting workload without significant data staleness.
Variation 2. A social media application stores user posts in an Amazon RDS for PostgreSQL instance. The application experiences a sudden spike in read traffic during peak hours, causing database bottlenecks. The team needs to improve read scalability without changing the application code. Which solution is MOST cost-effective?
hard
A.Migrate to Amazon DynamoDB with DAX
B.Enable Multi-AZ on the RDS instance
✓ C.Use Amazon RDS for PostgreSQL Read Replicas
D.Use Amazon ElastiCache to cache query results
Why C: Option C is correct because Amazon RDS for PostgreSQL Read Replicas allow you to offload read traffic from the primary DB instance to one or more read-only replicas, improving read scalability without any application code changes. This is the most cost-effective solution as it leverages the existing PostgreSQL engine and requires only minimal additional compute and storage costs for the replicas.
Last reviewed: Jun 20, 2026
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This DBS-C01 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 DBS-C01 exam.
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