- A
Use the STORING clause to include frequently queried columns in the index.
Storing columns in the index makes it a covering index, eliminating the need to read the base table.
- B
Convert the table to use hash-prefixed keys.
Why wrong: Hash-prefixed keys help with hot spots, not with covering queries.
- C
Create a new interleaved table and move the index data there.
Why wrong: Interleaved tables are for parent-child relationships, not for covering queries.
- D
Use the spanner_interleave_in_parent option when creating the index.
Why wrong: This option interleaves the index with the parent table, which can help locality but does not store additional columns.
Question 359 of 1,000
PCDE Optimising Service Performance Practice Question
This PCDE practice question tests your understanding of optimising service performance. 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.
Your Cloud Spanner database has a table with a secondary index that is used for range queries. You notice that the index queries are slow because they require back-and-forth between the index and the base table. How can you optimize the index to reduce this overhead?
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
✓
Use the STORING clause to include frequently queried columns in the index.
In Cloud Spanner, you can store additional columns from the base table in the secondary index using the STORING clause. This allows the index to satisfy queries without accessing the base table (covering index). INTERLEAVE IN PARENT for the index can also improve locality if the index is interleaved with a parent table. The question asks to reduce overhead of back-and-forth, which is solved by storing columns in the index.
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 the STORING clause to include frequently queried columns in the index.
Why this is correct
Storing columns in the index makes it a covering index, eliminating the need to read the base table.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Convert the table to use hash-prefixed keys.
Why it's wrong here
Hash-prefixed keys help with hot spots, not with covering queries.
- ✗
Create a new interleaved table and move the index data there.
Why it's wrong here
Interleaved tables are for parent-child relationships, not for covering queries.
- ✗
Use the spanner_interleave_in_parent option when creating the index.
Why it's wrong here
This option interleaves the index with the parent table, which can help locality but does not store additional columns.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which PCDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
- →
Optimising Service Performance — study guide chapter
Learn the concepts, then practise the questions
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Optimising Service Performance practice questions
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FAQ
Questions learners often ask
What does this PCDE question test?
Optimising Service Performance — This question tests Optimising Service Performance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use the STORING clause to include frequently queried columns in the index. — In Cloud Spanner, you can store additional columns from the base table in the secondary index using the STORING clause. This allows the index to satisfy queries without accessing the base table (covering index). INTERLEAVE IN PARENT for the index can also improve locality if the index is interleaved with a parent table. The question asks to reduce overhead of back-and-forth, which is solved by storing columns in the index.
What should I do if I get this PCDE question wrong?
Identify which PCDE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This PCDE 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 PCDE exam.
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