A fully PostgreSQL-compatible Google Cloud database service built for demanding workloads, with high transactional performance and a columnar engine that speeds up analytical queries on the same data.
On the ACE it is chosen when migrating a very demanding PostgreSQL database that needs more performance than Cloud SQL without changing engines. It supports managed backups and integrates with Database Center.
AlloyDB is a concept that can show up on the exam. Check the full guide to see it in context.