Cloud Digital Leader Practice Question: Google Cloud products, services, and solutions

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Cloud SQL (PostgreSQL)

  Why it's wrong here

  Cloud SQL (PostgreSQL) is a managed relational database that supports ACID transactions and SQL, but it is deployed as a regional resource. Although you can configure cross-region read replicas or use failover, the primary database does not automatically replicate writes across multiple regions with synchronous consistency. For a global financial transaction workload requiring low-latency writes and reads from multiple locations, Cloud SQL's regional architecture creates a single point of write locality and cannot provide the same global strong consistency as Cloud Spanner.

• ✓

  Cloud Spanner

  Why this is correct

  Cloud Spanner is the only option that combines full relational SQL support, ACID transactions, and automatic synchronous replication across multiple regions. It uses Paxos consensus and a TrueTime API to provide globally consistent read-write transactions with 99.999% availability. This makes it purpose-built for global financial transaction systems where customers expect consistent balances, complex queries, and horizontal scalability across regions. Its design directly addresses the need for both global distribution and strong transactional integrity.

• ✗

  Cloud Bigtable

  Why it's wrong here

  Cloud Bigtable is a NoSQL, wide-column key-value store optimized for high-throughput, low-latency analytical and operational workloads like IoT time-series or recommendation data. It does not support SQL queries, ACID multi-row transactions, or relational joins; it only offers atomic operations on individual rows. Financial transactions and reporting require multi-item consistency and rich querying, which Bigtable fundamentally lacks, making it unsuitable for this use case.

• ✗

  Firestore

  Why it's wrong here

  Firestore is a fully managed, globally distributed NoSQL document database that does support ACID transactions and multi-region replication with strong consistency. However, it is a document store, not a relational database, so it lacks full SQL query capabilities, complex joins, aggregations, and relational integrity constraints. Financial reporting and transaction processing often depend on ad-hoc SQL queries and normalized schemas, making Firestore a poor fit for such requirements despite its transactional guarantees.

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