- A
Use Cloud SQL instead if joins are needed.
Why wrong: Spanner supports joins efficiently with proper design.
- B
Design primary keys to distribute write load evenly across splits.
Good primary key design prevents hotspots and ensures scalability.
- C
Use interleaved tables to co-locate related rows.
Interleaved tables improve join performance by storing parent and child rows together.
- D
Store all data in a single table with JSON columns to avoid joins.
Why wrong: Spanner is relational; JSON columns are not optimized for joins.
- E
Create secondary indexes on columns used in WHERE clauses.
Secondary indexes enable efficient point lookups and range scans.
Question 372 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.
A team is designing a Spanner database for a global inventory system. They need to optimize query performance for frequently joined tables. Which THREE design decisions help achieve this? (Choose 3.)
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
✓
Design primary keys to distribute write load evenly across splits.
Option B is correct because Spanner uses distributed splits for scalability, and designing primary keys to avoid hotspots (e.g., using hash prefixes or monotonically increasing keys) ensures write load is evenly distributed across splits, preventing performance bottlenecks.
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.
- ✗
Use Cloud SQL instead if joins are needed.
Why it's wrong here
Spanner supports joins efficiently with proper design.
- ✓
Design primary keys to distribute write load evenly across splits.
Why this is correct
Good primary key design prevents hotspots and ensures scalability.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Use interleaved tables to co-locate related rows.
Why this is correct
Interleaved tables improve join performance by storing parent and child rows together.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Store all data in a single table with JSON columns to avoid joins.
Why it's wrong here
Spanner is relational; JSON columns are not optimized for joins.
- ✓
Create secondary indexes on columns used in WHERE clauses.
Why this is correct
Secondary indexes enable efficient point lookups and range scans.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that avoiding joins entirely (Option D) is a better optimization than properly using Spanner's native features like interleaving and secondary indexes, which are designed to handle joins efficiently at scale.
Detailed technical explanation
How to think about this question
Interleaved tables (Option C) physically co-locate parent and child rows in the same split, reducing cross-split reads and improving join performance. Secondary indexes (Option E) allow efficient lookup of rows by non-key columns, but in Spanner they are stored as separate tables that can introduce latency if not carefully designed; using a covering index can further reduce read costs.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
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
Learn the concepts, then practise the questions
- →
Storing the Data practice questions
Targeted practice on this topic area only
- →
All PDE questions
1,000 questions across all exam domains
- →
Google Professional Data Engineer study guide
Full concept coverage aligned to exam objectives
- →
PDE practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related PDE practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Designing Data Processing Systems practice questions
Practise PDE questions linked to Designing Data Processing Systems.
Ingesting and Processing the Data practice questions
Practise PDE questions linked to Ingesting and Processing the Data.
Storing the Data practice questions
Practise PDE questions linked to Storing the Data.
Preparing and Using Data for Analysis practice questions
Practise PDE questions linked to Preparing and Using Data for Analysis.
Maintaining and Automating Data Workloads practice questions
Practise PDE questions linked to Maintaining and Automating Data Workloads.
Building and operationalizing data processing systems practice questions
Practise PDE questions linked to Building and operationalizing data processing systems.
Operationalizing machine learning models practice questions
Practise PDE questions linked to Operationalizing machine learning models.
Ensuring solution quality practice questions
Practise PDE questions linked to Ensuring solution quality.
PDE fundamentals practice questions
Practise PDE questions linked to PDE fundamentals.
PDE scenario practice questions
Practise PDE questions linked to PDE scenario.
PDE troubleshooting practice questions
Practise PDE questions linked to PDE troubleshooting.
Practice this exam
Start a free PDE 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 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: Design primary keys to distribute write load evenly across splits. — Option B is correct because Spanner uses distributed splits for scalability, and designing primary keys to avoid hotspots (e.g., using hash prefixes or monotonically increasing keys) ensures write load is evenly distributed across splits, preventing performance bottlenecks.
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
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 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.
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.