Question 693 of 1,000
Google Cloud products, services, and solutionshardMultiple ChoiceObjective-mapped

Globally Distributed ACID Database on Google Cloud: Cloud Spanner vs Cloud SQL

This GCDL practice question tests your understanding of google cloud products, services, and solutions. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A global fintech company needs a database that can handle financial transactions across 50+ countries with consistent, ACID-compliant operations, SQL queries, and automatic global replication with no downtime for maintenance. Which Google Cloud database service meets all these requirements?

Quick Answer

The answer is Cloud Spanner. This is the correct choice because it is the only Google Cloud database that delivers ACID-compliant transactions with strong global consistency, full SQL support, and automatic synchronous replication across regions, all without downtime for maintenance. For a globally distributed ACID database on Google Cloud, Cloud Spanner uniquely combines horizontal scalability with the transactional guarantees required for financial operations across 50+ countries, whereas Cloud SQL is limited to a single region and cannot scale horizontally. On the Google Cloud Digital Leader exam, this question tests your understanding of when to choose Spanner over Cloud SQL, with a common trap being to select Cloud SQL for its familiarity—but remember, Cloud SQL lacks global replication and automatic failover. A useful memory tip: think of Spanner as the “global anchor” for ACID—if your data needs to span continents with zero downtime, Spanner is the only Spanner in the works.

Answer choices

Why each option matters

Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.

Correct answer & explanation

Cloud Spanner

Cloud Spanner is the only Google Cloud database that provides ACID-compliant transactions, full SQL support, and automatic synchronous global replication with no downtime for maintenance. It is designed for horizontally scalable, globally distributed applications that require strong consistency across regions, making it the ideal choice for a fintech company operating in 50+ countries.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

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 is a regional database — it doesn't automatically replicate globally. Cross-region failover is supported but not automatic global distribution with consistent transactions.

  • Cloud Spanner

    Why this is correct

    Cloud Spanner provides ACID transactions, SQL support, and automatic global replication across multiple regions with 99.999% availability. It's designed for exactly this global financial transaction use case.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Cloud Bigtable

    Why it's wrong here

    Bigtable is a NoSQL database (key-value) optimized for high-throughput non-transactional workloads. It doesn't support ACID transactions or SQL queries.

  • Firestore

    Why it's wrong here

    Firestore supports ACID transactions and global distribution but is a NoSQL document database — it lacks full SQL query capabilities required for financial reporting and complex joins.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The GCDL exam often tests the misconception that Cloud SQL can be made globally consistent with replication, but Cloud SQL replicas are read-only and asynchronous, so they cannot provide the strong ACID writes across regions that Cloud Spanner offers.

Detailed technical explanation

How to think about this question

Cloud Spanner uses a combination of TrueTime (Google's globally synchronized clock) and the Paxos consensus protocol to provide external consistency (linearizability) across all replicas, even during automatic failover or resharding. This allows it to maintain ACID transactions across continents without the performance penalty of traditional two-phase commit, as it uses a distributed query optimizer and interleaved tables to reduce cross-node coordination. In a real-world scenario, a fintech app processing cross-border payments can read and write the same account balance from any region and always see the latest committed state, which is impossible with eventually consistent systems.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.

What to study next

Got this wrong? Here's your next step.

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FAQ

Questions learners often ask

What does this GCDL question test?

Google Cloud products, services, and solutions — This question tests Google Cloud products, services, and solutions — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Cloud Spanner — Cloud Spanner is the only Google Cloud database that provides ACID-compliant transactions, full SQL support, and automatic synchronous global replication with no downtime for maintenance. It is designed for horizontally scalable, globally distributed applications that require strong consistency across regions, making it the ideal choice for a fintech company operating in 50+ countries.

What should I do if I get this GCDL question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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This GCDL practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the GCDL exam.