DBS-C01 Management and Operations Practice Question
A company has a production Amazon Aurora MySQL DB cluster with one writer and two reader instances. The application uses a custom connection pool that uses the writer endpoint for all database calls. The application is experiencing increased latency during peak hours. A database specialist suggests using the reader endpoint for read-only queries. What change is required on the application side to implement this recommendation?
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
✓
Update the application's connection logic to use the cluster endpoint for writes and the reader endpoint for reads.
The application needs to differentiate between read and write queries and send read queries to the reader endpoint while write queries continue to use the writer endpoint. No changes to the Aurora cluster are needed; Aurora automatically handles connectivity to reader instances via the reader endpoint. The cluster endpoint remains unchanged for writes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Modify the Aurora cluster to enable load balancing for the reader endpoint.
Why it's wrong here
Load balancing is inherent; no explicit modification needed.
- ✗
Create a new custom endpoint for read-only queries and use it instead of the reader endpoint.
Why it's wrong here
The reader endpoint is already suitable; a custom endpoint is unnecessary unless specific routing is needed.
- ✗
Replace the writer endpoint with the reader endpoint in the connection pool configuration.
Why it's wrong here
This would break write operations because the reader endpoint only handles read traffic.
- ✓
Update the application's connection logic to use the cluster endpoint for writes and the reader endpoint for reads.
Why this is correct
The reader endpoint distributes read traffic across all reader instances, reducing writer load.
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Same concept, more angles
3 more ways this is tested on DBS-C01
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Variation 1. A company runs an Amazon Aurora MySQL DB cluster with one writer and two readers. The application experiences increased read latency. The DBA wants to offload read traffic from the writer instance. Which configuration change should be made to the application?
easy- A.Modify the application to use an individual instance endpoint for each reader.
- B.Create a custom endpoint that includes both writer and readers.
- ✓ C.Modify the application to use the reader endpoint for read queries.
- D.Modify the application to use the cluster endpoint for all queries.
Why C: The reader endpoint for an Aurora MySQL cluster automatically load-balances read-only connections across all available reader instances. By modifying the application to use the reader endpoint for read queries, read traffic is offloaded from the writer instance, reducing read latency on the writer. This is the standard AWS-recommended pattern for separating read and write workloads in Aurora.
Variation 2. A company has an Amazon Aurora MySQL DB cluster with a single writer and two readers. The writer instance fails, and the failover mechanism promotes one of the readers to writer. The application, which uses a custom connection pool, continues to experience errors for several minutes. What should the database administrator do to minimize downtime during future failovers?
easy- A.Increase the connection pool size to handle more connections.
- ✓ B.Modify the application to use the cluster endpoint instead of the instance endpoint.
- C.Configure the application to use the reader endpoint for all traffic.
- D.Enable Multi-AZ on the Aurora cluster.
Why B: The cluster endpoint always points to the current writer, so after a failover it automatically routes to the new writer without application changes. Option A is wrong because increasing the connection pool size does not help the application detect the new writer; it could even cause more failed connections. Option C is wrong because the reader endpoint only routes to read replicas, not the writer, so write traffic would fail. Option D is wrong because Aurora already provides Multi-AZ replication; there is no separate 'enable Multi-AZ' setting.
Variation 3. A database engineer is troubleshooting an Amazon Aurora MySQL DB cluster that is experiencing frequent failovers. The failovers are occurring during periods of low write activity. The engineer notices that the primary instance's writer endpoint is being used for read traffic from a legacy application. What is the most likely cause of the failovers?
medium- A.A high replication lag between the primary and replica instances
- B.A long-running write transaction is blocking the failover
- C.Insufficient storage for the Aurora cluster volume
- ✓ D.The primary instance is overloaded due to read traffic from the writer endpoint
Why D: Using the writer endpoint for read traffic can overload the primary instance, leading to resource contention and failovers even during low write activity. Option A is incorrect because replication lag is not a direct cause of failovers; failovers are typically due to primary instance issues. Option B is incorrect because a long-running write transaction would not cause failovers during low write activity; it might cause replication lag but not failover. Option C is incorrect because insufficient storage for the Aurora cluster volume would cause storage-related errors, not failovers; Aurora automatically scales storage.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.