Which solution will improve the website’s performance?
Use an RDS PostgreSQL DB instance instead of a MySQL database.
Use Amazon ElastiCache to cache the query responses for the website.
Add an additional Availability Zone to the current RDS MySQL Multi-AZ DB instance.
Add a read replica to the RDS DB instance and configure the internal systems to query the read replica.
Explanations:
Switching to PostgreSQL may not inherently resolve performance issues related to data fetching; the underlying problem is the load on the current MySQL instance.
While using Amazon ElastiCache can help by caching frequent queries, it does not address the root issue of heavy querying affecting the database performance directly.
Adding an additional Availability Zone to a Multi-AZ setup improves availability and disaster recovery but does not enhance performance or distribute the load for read operations.
Adding a read replica offloads read traffic from the primary instance, allowing internal systems to query the replica instead, which improves performance for both the website and the internal systems.
I organize that the answer is:
Add a read replica to the RDS DB instance and configure the internal systems to query the read replica.