An RDS database handles an extremely high volume of read queries. Which feature is effective for distributing read traffic and improving the read performance of the application?
A question asking to select the RDS feature for distributing read traffic and improving read performance.
Multi-AZ deployment
Multi-AZ is a standby configuration designed to improve availability, and the standby instance is not normally used for reads.
The read replica is more suitable for the purpose of distributing read traffic described in this question, so this is incorrect.
Use DynamoDB Accelerator (DAX).
DAX is an in-memory cache dedicated to DynamoDB that accelerates DynamoDB reads to microseconds.
Because it is dedicated to DynamoDB (NoSQL), it cannot be used to distribute read traffic for an RDS relational database, so this is incorrect.
Scale up the instance to a larger type.
Scaling up increases the processing capacity of a single instance, which improves read performance to some extent.
However, it does not distribute the load across multiple instances, and it has limitations around cost, ceiling, and restart during change. A read replica is more appropriate for distributing read traffic as described in this question, so this is incorrect.
Read replica
This is correct. A read replica creates read-only copies of the primary DB and routes read queries to them, distributing the read load. It is effective for improving read scalability for read-heavy workloads.
Read replica = read scalability (distributing read traffic); Multi-AZ = availability (automatic failover). 'High read volume / performance' points to read replica; 'continuity during failure' points to Multi-AZ.