Amazon Relational Database Service (Amazon RDS) for PostgreSQL now supports Amazon RDS Optimized Reads for up to two times faster query processing compared to previous generation instances. Complex queries that utilize temporary tables, such as queries involving sorts, hash aggregations, high-load joins, and Common Table Expressions (CTEs) can now execute up to two times faster with Optimized Reads on RDS for PostgreSQL. Optimized Read-enabled instances achieve faster query processing by placing temporary tables generated by PostgreSQL on the local NVMe-based SSD block-level storage, thereby reducing your traffic to Elastic Block Storage (EBS) over the network. Refer to our recent blog post to learn more about performance improvements using local disk based database instances for workloads that have highly concurrent read/write processing.
Source:: Amazon AWS