- A
Create a secondary index on the primary key column.
Why wrong: A secondary index on primary key is redundant and won't improve read latency.
- B
Increase the number of Spanner nodes to distribute the load.
Why wrong: Adding nodes increases capacity but does not reduce geographic read latency.
- C
Use read-only transactions with stale reads (timestamp bound) to read from local replicas.
Stale reads allow Spanner to serve reads from the nearest replica, reducing latency for far-away users.
- D
Partition the database by region and use directed reads.
Why wrong: Partitioning by region is not recommended as it adds complexity; directed reads are not a feature for Spanner.
Quick Answer
The answer is to use read-only transactions with stale reads (timestamp bound) to read from local replicas. This is correct because Cloud Spanner’s multi-region configuration, such as nam7, deploys regional replicas in Europe, and stale reads allow read-only transactions to be served from the nearest replica without waiting for the most recent write timestamp. By accepting a small, bounded staleness, you eliminate cross-region round trips, directly reducing read latency for European users while still providing strongly consistent reads within the staleness window. On the Google Professional Cloud Database Engineer exam, this scenario tests your understanding of Spanner’s replication model and the trade-off between consistency and latency—a common trap is assuming all reads must be strong reads, which forces leader-based routing across regions. Remember the memory tip: “Stale is fast, strong is far”—if your application can tolerate a few seconds of staleness, always bind a timestamp to keep reads local.
PCDE Plan and manage database infrastructure Practice Question
This PCDE practice question tests your understanding of plan and manage database infrastructure. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 uses Cloud Spanner with a multi-region configuration (nam7) to support a global user base. They notice increased read latency for users in Europe, while write latency is acceptable. The database engineer observes that most queries are single-row reads using the primary key. What is the best approach to reduce read latency for European users?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 read-only transactions with stale reads (timestamp bound) to read from local replicas.
Option C is correct because Cloud Spanner's multi-region configuration (nam7) includes regional replicas in Europe. By using stale reads with a timestamp bound, read-only transactions can be served from a local replica without incurring cross-region latency, which directly reduces read latency for European users while maintaining acceptable consistency.
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.
- ✗
Create a secondary index on the primary key column.
Why it's wrong here
A secondary index on primary key is redundant and won't improve read latency.
- ✗
Increase the number of Spanner nodes to distribute the load.
Why it's wrong here
Adding nodes increases capacity but does not reduce geographic read latency.
- ✓
Use read-only transactions with stale reads (timestamp bound) to read from local replicas.
Why this is correct
Stale reads allow Spanner to serve reads from the nearest replica, reducing latency for far-away users.
Clue confirmation
The clue words "best", "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Partition the database by region and use directed reads.
Why it's wrong here
Partitioning by region is not recommended as it adds complexity; directed reads are not a feature for Spanner.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that increasing nodes or adding indexes solves geographic latency, when the real solution is leveraging replica locality via stale reads or read-only transactions.
Detailed technical explanation
How to think about this question
In Cloud Spanner, a multi-region configuration like nam7 has a default leader region (e.g., us-central1) and one or more witness or read-only replicas in other regions (e.g., europe-west1). Stale reads with a timestamp bound (e.g., exact_staleness or max_staleness) allow read-only transactions to be served from any replica that has data up to that timestamp, avoiding the need to contact the leader region. This is particularly effective for single-row primary key reads, which are deterministic and can be served locally with minimal staleness (e.g., 10–15 seconds).
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
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.
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FAQ
Questions learners often ask
What does this PCDE question test?
Plan and manage database infrastructure — This question tests Plan and manage database infrastructure — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use read-only transactions with stale reads (timestamp bound) to read from local replicas. — Option C is correct because Cloud Spanner's multi-region configuration (nam7) includes regional replicas in Europe. By using stale reads with a timestamp bound, read-only transactions can be served from a local replica without incurring cross-region latency, which directly reduces read latency for European users while maintaining acceptable consistency.
What should I do if I get this PCDE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "best", "primary". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Same concept, more angles
1 more ways this is tested on PCDE
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company's Cloud Spanner database currently uses a regional configuration in us-central1. Due to growth, the database must support global reads with low latency and maintain strong consistency. The database engineer is evaluating options. Which THREE considerations should the engineer include in the design? (Choose three.)
hard- A.Use interleaved tables to reduce the number of reads required for hierarchical data.
- ✓ B.Select a configuration that places the leader region close to the majority of write traffic.
- ✓ C.Ensure the schema uses primary keys that distribute writes evenly across nodes.
- D.Add read replicas in remote regions to serve reads with eventual consistency.
- ✓ E.Use a multi-region instance configuration that includes multiple read-write regions.
Why B: Option B is correct because in a multi-region Cloud Spanner configuration, the leader region handles all writes and must be placed close to the majority of write traffic to minimize write latency. This ensures strong consistency, as all reads are served from the same leader region by default, and global reads with low latency require careful leader placement to avoid cross-region round trips.
Last reviewed: Jun 30, 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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