- A
Firestore
Why wrong: Firestore is a document NoSQL database, not SQL, and its global consistency is eventual unless using transactions.
- B
Cloud SQL
Why wrong: Cloud SQL is regional, not globally distributed, and its SLA is lower (99.95% for single zone).
- C
Cloud Spanner
Spanner is globally distributed, provides strong consistency, and offers 99.999% availability SLA, matching the requirements.
- D
Cloud Bigtable
Why wrong: Bigtable is a NoSQL wide-column database, not SQL, and does not offer strong transactional consistency across regions.
Question 175 of 1,000
PDE Storing the Data Practice Question
This PDE practice question tests your understanding of storing the data. 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.
An organization needs to store transactional data for a global e-commerce platform with strong consistency across regions and an SLA of 99.999% availability. The application requires SQL semantics with horizontal scaling. Which Google Cloud database should they choose?
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 correct choice because it provides globally distributed, strongly consistent SQL semantics with horizontal scaling and a 99.999% availability SLA. It uses synchronous replication and the TrueTime API to ensure external consistency across regions, meeting the strict consistency and uptime requirements of a global e-commerce platform.
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.
- ✗
Firestore
Why it's wrong here
Firestore is a document NoSQL database, not SQL, and its global consistency is eventual unless using transactions.
- ✗
Cloud SQL
Why it's wrong here
Cloud SQL is regional, not globally distributed, and its SLA is lower (99.95% for single zone).
- ✓
Cloud Spanner
Why this is correct
Spanner is globally distributed, provides strong consistency, and offers 99.999% availability SLA, matching the requirements.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Cloud Bigtable
Why it's wrong here
Bigtable is a NoSQL wide-column database, not SQL, and does not offer strong transactional consistency across regions.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Cloud Spanner with Cloud SQL, assuming any SQL database can scale horizontally, but Cloud SQL is a single-region, vertically scaled service, while Spanner is the only Google Cloud database that combines SQL, horizontal scaling, and global strong consistency with a 99.999% SLA.
Detailed technical explanation
How to think about this question
Cloud Spanner achieves global strong consistency through the TrueTime API, which uses GPS and atomic clocks to assign globally consistent timestamps, enabling external consistency for distributed transactions. It employs synchronous replication across zones and regions using the Paxos protocol, ensuring that all reads and writes are linearizable. In a real-world scenario, a global e-commerce platform using Spanner can run ACID transactions across continents without sacrificing performance, as Spanner automatically handles sharding and load balancing.
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
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Storing the Data — study guide chapter
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Storing the Data practice questions
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FAQ
Questions learners often ask
What does this PDE question test?
Storing the Data — This question tests Storing the Data — 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 correct choice because it provides globally distributed, strongly consistent SQL semantics with horizontal scaling and a 99.999% availability SLA. It uses synchronous replication and the TrueTime API to ensure external consistency across regions, meeting the strict consistency and uptime requirements of a global e-commerce platform.
What should I do if I get this PDE 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
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Last reviewed: Jul 4, 2026
This PDE 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 PDE exam.
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