Which solution will meet this requirement with LEAST current and future effort?
Use a multi-AZ Amazon RDS deployment. Increase the number of connections that the code makes to the database or increase the connection pool size if a connection pool is in use.
Use a multi-AZ Amazon RDS deployment. Modify the code so that queries access the secondary RDS instance.
Deploy Amazon RDS with one or more read replicas. Modify the application code so that queries use the URL for the read replicas.
Use open source replication software to create a copy of the MySQL database on an Amazon EC2 instance. Modify the application code so that queries use the IP address of the EC2 instance.
Explanations:
Using a multi-AZ deployment enhances availability and failover capabilities but does not optimize read performance. Increasing the number of connections may lead to contention and performance issues rather than improving read efficiency.
A multi-AZ deployment is primarily for high availability and automatic failover, not for load balancing read queries. Accessing the secondary instance is not possible, as it is a standby replica and not intended for read traffic.
Deploying RDS with read replicas allows the distribution of read traffic across multiple instances, significantly improving read performance. Modifying the application to direct read queries to the read replicas ensures optimal resource utilization with minimal code changes.
While using open-source replication to create a copy of the database may work, it introduces complexity and potential latency issues. Additionally, managing an EC2 instance for replication requires more effort for maintenance and monitoring compared to using managed RDS features.
I suspect that the answer is:
Deploy Amazon RDS with one or more read replicas. Modify the application code so that queries use the URL for the read replicas.