A SaaS startup runs an order-management application that needs a managed PostgreSQL database with automated backups, point-in-time recovery and automatic maintenance. It does not need writes in multiple regions. Which service is the best fit?
Show answer and explanation
Answer: D
Cloud SQL for PostgreSQL is a managed relational service that handles backups, point-in-time recovery, patching and high availability for a standard PostgreSQL engine. The startup keeps familiar PostgreSQL behavior and drivers without running database servers. Spanner would work but adds cost and a distributed design the requirements do not need, while Bigtable and Firestore are non-relational stores.
Why the other options are wrong
- A. Firestore in Datastore mode is a document database with no PostgreSQL compatibility, so the application's relational queries and PostgreSQL drivers would not work without a rewrite.
- B. Bigtable is a wide-column NoSQL store with no SQL joins or PostgreSQL wire compatibility, so it cannot host this relational application.
- C. Spanner does support relational SQL, but it is a distributed service with its own dialect, and the scenario does not require global scale, so it adds unnecessary cost and migration effort.