An application is slow under increased read demand. The reads are for historical, read-only records retrieved from an Amazon RDS database using custom views and queries. You must improve performance without modifying the database schema and minimize management overhead. Which approach will achieve this?

Deploying Amazon ElastiCache (Redis OSS) is the most suitable solution. ElastiCache is a fully managed in-memory caching service that significantly improves read performance for frequently accessed data by retrieving it from a fast cache instead of repeatedly querying the database. Redis OSS supports complex data structures, making it effective for caching results from custom views and queries. This approach minimizes management overhead as ElastiCache handles patching, backups, and scaling. Migrating all data to Amazon DynamoDB would involve significant schema changes and application refactoring, which the problem statement explicitly forbids. Deploying Memcached on Amazon EC2 would require managing the EC2 instance, the Memcached software, and scaling, increasing management overhead compared to a fully managed service like ElastiCache. Amazon DynamoDB Accelerator (DAX) is designed exclusively for Amazon DynamoDB and cannot be used with Amazon RDS.