A read replica is a synchronized database instance that serves read operations separately from a primary writable instance. Route SELECT queries to replicas so the primary can focus on writes and remaining database work. section 6.4.1
Prepare for this pattern before scaling by using two application database connections to the same database. Give the second connection a read-only user, then change its instance address when an actual replica is deployed. section 6.4.1
Preparing an application connection
Configure the primary connection for normal read/write access and a separate read-only connection for SELECT queries. Initially both may point to one database; later, point the second connection at the read replica. section 6.4.1
