- A
Cloud SQL with read replicas in multiple regions
Why wrong: Cloud SQL with read replicas provides read scaling but writes remain single-region. Global write consistency across regions requires manual application-level sharding, complex failover, and introduces latency inconsistencies. Cloud SQL does not natively provide globally consistent low-latency writes.
- B
Cloud Spanner, Google's globally distributed relational database with ACID transactions and horizontal scalability
Cloud Spanner uniquely satisfies all three requirements: full ACID compliance for financial transactions, global distribution with strong consistency for low-latency global reads and writes, and horizontal scaling without downtime. It was purpose-built by Google for exactly this class of globally consistent, highly available transactional workloads.
- C
Firestore in Datastore mode with multi-region replication
Why wrong: Firestore is a NoSQL document database that provides eventual or strong consistency per-document but not ACID transactions across multiple document types. It is not suitable for complex relational financial transaction processing.
- D
BigQuery with streaming inserts for real-time transaction processing
Why wrong: BigQuery is an analytical data warehouse, not a transactional database. It does not provide ACID transaction support for the type of concurrent read-write financial transaction processing described.
Quick Answer
The answer is Cloud Spanner, the only globally distributed relational database with ACID transactions. This is correct because Cloud Spanner uniquely combines horizontal scalability with strict ACID compliance across regions, using Google’s TrueTime API and synchronous replication to deliver consistent low-latency reads and writes worldwide—no other Google Cloud database service can meet all three requirements simultaneously. On the Google Cloud Digital Leader exam, this question tests your understanding of when to choose Spanner over Bigtable (which is not ACID-compliant) or Cloud SQL (which cannot scale globally without downtime). A common trap is assuming any relational database can handle global transactions, but only Spanner offers automatic sharding and resharding without maintenance windows. Memory tip: think “Spanner spans the globe with ACID”—if you need global consistency and horizontal scaling, Spanner is the only answer.
Cloud Digital Leader Practice Question: Google Cloud products, services, and solutions
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 retail company needs to process financial transactions requiring strict ACID compliance, serve global customers with consistent low-latency reads and writes, and scale horizontally without downtime for maintenance. Which Google Cloud database service is uniquely designed to meet all three requirements simultaneously?
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, Google's globally distributed relational database with ACID transactions and horizontal scalability
Cloud Spanner is the only Google Cloud database service that simultaneously provides ACID compliance across global transactions, consistent low-latency reads and writes via TrueTime and synchronous replication, and horizontal scaling without downtime through automatic sharding and resharding. It uniquely combines relational database semantics with global distribution, making it the correct choice for the given requirements.
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 with read replicas in multiple regions
Why it's wrong here
Cloud SQL with read replicas provides read scaling but writes remain single-region. Global write consistency across regions requires manual application-level sharding, complex failover, and introduces latency inconsistencies. Cloud SQL does not natively provide globally consistent low-latency writes.
- ✓
Cloud Spanner, Google's globally distributed relational database with ACID transactions and horizontal scalability
Why this is correct
Cloud Spanner uniquely satisfies all three requirements: full ACID compliance for financial transactions, global distribution with strong consistency for low-latency global reads and writes, and horizontal scaling without downtime. It was purpose-built by Google for exactly this class of globally consistent, highly available transactional workloads.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Firestore in Datastore mode with multi-region replication
Why it's wrong here
Firestore is a NoSQL document database that provides eventual or strong consistency per-document but not ACID transactions across multiple document types. It is not suitable for complex relational financial transaction processing.
- ✗
BigQuery with streaming inserts for real-time transaction processing
Why it's wrong here
BigQuery is an analytical data warehouse, not a transactional database. It does not provide ACID transaction support for the type of concurrent read-write financial transaction processing described.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that a globally distributed NoSQL database like Firestore can provide ACID compliance, but Firestore only supports single-entity transactions and lacks the strict consistency needed for financial transactions.
Detailed technical explanation
How to think about this question
Cloud Spanner uses TrueTime, a globally synchronized clock based on GPS and atomic clocks, to enforce external consistency and provide linearizable transactions across regions. It employs synchronous replication using Paxos-based consensus to ensure data durability and consistency, while automatic sharding (splitting) and resharding allow it to scale horizontally without downtime. In a real-world scenario, a global payment system can use Spanner to process a transfer from a US bank to a European bank with ACID guarantees and sub-100ms latency, even as data is replicated across continents.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
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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, Google's globally distributed relational database with ACID transactions and horizontal scalability — Cloud Spanner is the only Google Cloud database service that simultaneously provides ACID compliance across global transactions, consistent low-latency reads and writes via TrueTime and synchronous replication, and horizontal scaling without downtime through automatic sharding and resharding. It uniquely combines relational database semantics with global distribution, making it the correct choice for the given requirements.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 30, 2026
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.
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