RDS for MySQL and PostgreSQL support read replicas to offload read traffic from primary DB instances.
Both primary DB instances and read replicas of RDS MySQL and PostgreSQL databases have independent connection addresses. Each RDS MySQL or PostgreSQL database of the basic edition and high-availability edition supports a maximum of five read replicas. For details about how to create a read replica, see section Creating a Read Replica.
To improve the system processing capability, you do not need to change applications. You only need to create read replicas.