These questions are independently created for study purposes. They are not official AWS exam questions, actual exam questions, leaked questions, or exam dumps.
SAA-017
You have an RDS for PostgreSQL instance with heavy read load. Write load is low, and you want to scale read queries. Which configuration is the most appropriate?
Choices
Explanation and answer
Read the explanation and correct answer (spoiler — try answering first)
Correct answer: A. Add Read Replicas and route read queries to the Read Replicas.
Explanation
Read Replicas are used for read scaling. Having the application route reads to replicas reduces the read load on the primary DB.
Per-choice explanations
A. Add Read Replicas and route read queries to the Read Replicas.
Correct. It is suited to distributing read load.
B. Disable RDS automated backups.
Incorrect. Disabling backups is not a performance improvement and reduces recoverability.
C. Move the DB to a public subnet.
Incorrect. Moving to a public subnet does not improve performance and increases security risk.
D. Enable Multi-AZ and send read queries to the standby DB.
Incorrect. The RDS Multi-AZ standby DB is generally not used for reads.
Practical Use
RDS Read Replicas are read-only DB instances created from the primary DB via asynchronous replication and are used as targets to distribute read queries. They are supported for MySQL, MariaDB, PostgreSQL, Oracle, SQL Server, and Aurora engines. By routing writes to the primary and reads to replicas in the application, you can lower the read load on the primary and scale out read throughput by adding replicas horizontally. With Aurora, you can have up to 15 replicas in the same cluster, and a dedicated endpoint (the reader endpoint) automatically load-balances among them. A caveat is that replicas use asynchronous replication, so data written just before may not be readable immediately (replication lag). Reads that require strong consistency should go to the primary, or the application should branch to read from the primary right after a write. Multi-AZ deployment is for availability, and its standby DB cannot be used for reads (it is reserved for failover). Availability and scalability are separate design concerns. To meet both, combine Multi-AZ with Read Replicas. On SAA-C03, when keywords such as "heavy read load," "scale read queries," or "write load is unchanged" appear, Read Replicas are the correct answer. Distractors include "Multi-AZ also distributes reads," "increase the instance type (vertical scaling) only," or "cache all queries in ElastiCache," each of which substitutes a different scaling direction or service role.