- A
Cloud Spanner
Why wrong: Spanner is not PostgreSQL-compatible and does not offer 4x speedup.
- B
Cloud SQL for PostgreSQL
Why wrong: Does not offer 4x OLTP speedup or built-in columnar analytics.
- C
AlloyDB
AlloyDB provides 4x faster OLTP, PostgreSQL compatibility, and in-database analytics.
- D
BigQuery
Why wrong: BigQuery is a separate analytics system, not an OLTP database.
Question 439 of 999
Design Scalable and Highly Available Cloud Database Solutions →mediumMultiple ChoiceObjective-mapped
PCD Practice Question: Design Scalable and Highly Available Cloud Database Solutions
This PCD practice question tests your understanding of design scalable and highly available cloud database 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 company needs to run a PostgreSQL-compatible database with 4x faster OLTP performance than standard PostgreSQL, and also wants to run analytical queries on the same data without extracting to a separate system. 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
✓
AlloyDB
AlloyDB is a PostgreSQL-compatible database that delivers up to 4x faster OLTP performance than standard PostgreSQL through a combination of a columnar engine, adaptive indexing, and a disaggregated storage architecture. It also supports running analytical queries on the same data without extraction, using its built-in columnar engine for fast analytics on transactional data.
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 Spanner
Why it's wrong here
Spanner is not PostgreSQL-compatible and does not offer 4x speedup.
- ✗
Cloud SQL for PostgreSQL
Why it's wrong here
Does not offer 4x OLTP speedup or built-in columnar analytics.
- ✓
AlloyDB
Why this is correct
AlloyDB provides 4x faster OLTP, PostgreSQL compatibility, and in-database analytics.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
BigQuery
Why it's wrong here
BigQuery is a separate analytics system, not an OLTP database.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse Cloud SQL for PostgreSQL as the obvious choice for PostgreSQL compatibility, overlooking the specific performance requirement of 4x faster OLTP and the need for built-in analytical capabilities, which only AlloyDB satisfies.
Detailed technical explanation
How to think about this question
AlloyDB achieves its performance gains through a disaggregated storage layer that uses a log-structured merge-tree (LSM) approach with a columnar engine for analytics, allowing it to serve both OLTP and OLAP workloads on the same data without ETL. Under the hood, AlloyDB's adaptive indexing automatically creates and maintains indexes based on query patterns, reducing manual tuning. In a real-world scenario, an e-commerce platform could use AlloyDB to handle high-velocity order transactions while simultaneously running real-time sales analytics on the same dataset, avoiding the latency and complexity of data replication.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
- →
Design Scalable and Highly Available Cloud Database Solutions — study guide chapter
Learn the concepts, then practise the questions
- →
Design Scalable and Highly Available Cloud Database Solutions practice questions
Targeted practice on this topic area only
- →
All PCD questions
999 questions across all exam domains
- →
Google Professional Cloud Developer study guide
Full concept coverage aligned to exam objectives
- →
PCD practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related PCD practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Manage a Solution that Can Span Multiple Database Systems practice questions
Practise PCD questions linked to Manage a Solution that Can Span Multiple Database Systems.
Deploy Scalable and Highly Available Databases in Google Cloud practice questions
Practise PCD questions linked to Deploy Scalable and Highly Available Databases in Google Cloud.
Design Scalable and Highly Available Cloud Database Solutions practice questions
Practise PCD questions linked to Design Scalable and Highly Available Cloud Database Solutions.
Migrate Data Solutions practice questions
Practise PCD questions linked to Migrate Data Solutions.
Designing highly scalable, available, and reliable cloud-native applications practice questions
Practise PCD questions linked to Designing highly scalable, available, and reliable cloud-native applications.
Building and testing applications practice questions
Practise PCD questions linked to Building and testing applications.
Deploying applications practice questions
Practise PCD questions linked to Deploying applications.
Integrating Google Cloud services practice questions
Practise PCD questions linked to Integrating Google Cloud services.
Managing application performance monitoring practice questions
Practise PCD questions linked to Managing application performance monitoring.
PCD fundamentals practice questions
Practise PCD questions linked to PCD fundamentals.
PCD scenario practice questions
Practise PCD questions linked to PCD scenario.
PCD troubleshooting practice questions
Practise PCD questions linked to PCD troubleshooting.
Practice this exam
Start a free PCD practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this PCD question test?
Design Scalable and Highly Available Cloud Database Solutions — This question tests Design Scalable and Highly Available Cloud Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: AlloyDB — AlloyDB is a PostgreSQL-compatible database that delivers up to 4x faster OLTP performance than standard PostgreSQL through a combination of a columnar engine, adaptive indexing, and a disaggregated storage architecture. It also supports running analytical queries on the same data without extraction, using its built-in columnar engine for fast analytics on transactional data.
What should I do if I get this PCD 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: Jul 4, 2026
This PCD 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 PCD exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.