- A
The application's session is pinned to a secondary replica despite requesting the primary.
Why wrong: Session pinning does not override read preference; if primary is requested, the driver connects to primary.
- B
The application is using a read preference that allows secondary reads.
If the read preference is set to 'secondaryPreferred' or similar, reads may go to secondary replicas which are eventually consistent.
- C
The primary instance is experiencing high CPU utilization, causing delayed writes.
Why wrong: High CPU on primary does not cause stale reads on primary; writes are acknowledged before responding.
- D
The storage volume is using the default eventually consistent configuration for primary reads.
Why wrong: DocumentDB primary reads are strongly consistent by default.
Quick Answer
The answer is a read preference that allows secondary reads. This is the most likely cause because Amazon DocumentDB, while offering strongly consistent reads from the primary instance by default, uses a distributed storage volume with six copies across three Availability Zones where secondary replicas are eventually consistent. If the application’s read preference is set to 'secondaryPreferred' or any value that permits reads from a replica—even when the primary is available—those reads can return stale data. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of how DocumentDB’s consistency model interacts with MongoDB-compatible read preferences, a common trap where candidates assume all reads are strongly consistent simply because they target the primary. A useful memory tip is: “Primary equals strong, secondary equals eventual—check your preference to prevent stale.”
DBS-C01 Workload-Specific Database Design Practice Question
This DBS-C01 practice question tests your understanding of workload-specific database design. 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 runs a MongoDB-compatible workload on Amazon DocumentDB. They notice that many read requests are returning stale data even though reads are directed to the primary instance. What is the MOST likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
The application is using a read preference that allows secondary reads.
DocumentDB uses a distributed storage volume with six copies across three Availability Zones. Reads from the primary are strongly consistent by default. However, if the application uses read preferences that allow secondary reads (e.g., 'secondaryPreferred'), then reads may go to replicas which are eventually consistent. The question implies reads are directed to primary, but if the application uses 'secondaryPreferred' and the primary is unavailable, reads may go to secondary. Alternatively, if the application uses a read preference that does not require primary, stale reads can occur. Option D addresses the most common cause: read preference set to allow secondary reads.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The application's session is pinned to a secondary replica despite requesting the primary.
Why it's wrong here
Session pinning does not override read preference; if primary is requested, the driver connects to primary.
- ✓
The application is using a read preference that allows secondary reads.
Why this is correct
If the read preference is set to 'secondaryPreferred' or similar, reads may go to secondary replicas which are eventually consistent.
Clue confirmation
The clue words "most likely", "primary" in the question point toward this answer.
Related concept
Static NAT maps one inside address to one outside address.
- ✗
The primary instance is experiencing high CPU utilization, causing delayed writes.
Why it's wrong here
High CPU on primary does not cause stale reads on primary; writes are acknowledged before responding.
- ✗
The storage volume is using the default eventually consistent configuration for primary reads.
Why it's wrong here
DocumentDB primary reads are strongly consistent by default.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
- →
Workload-Specific Database Design — study guide chapter
Learn the concepts, then practise the questions
- →
Workload-Specific Database Design practice questions
Targeted practice on this topic area only
- →
All DBS-C01 questions
1,730 questions across all exam domains
- →
AWS Certified Database Specialty DBS-C01 study guide
Full concept coverage aligned to exam objectives
- →
DBS-C01 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related DBS-C01 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Workload-Specific Database Design practice questions
Practise DBS-C01 questions linked to Workload-Specific Database Design.
Deployment and Migration practice questions
Practise DBS-C01 questions linked to Deployment and Migration.
Management and Operations practice questions
Practise DBS-C01 questions linked to Management and Operations.
Monitoring and Troubleshooting practice questions
Practise DBS-C01 questions linked to Monitoring and Troubleshooting.
Database Security practice questions
Practise DBS-C01 questions linked to Database Security.
DBS-C01 fundamentals practice questions
Practise DBS-C01 questions linked to DBS-C01 fundamentals.
DBS-C01 scenario practice questions
Practise DBS-C01 questions linked to DBS-C01 scenario.
DBS-C01 troubleshooting practice questions
Practise DBS-C01 questions linked to DBS-C01 troubleshooting.
Practice this exam
Start a free DBS-C01 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 DBS-C01 question test?
Workload-Specific Database Design — This question tests Workload-Specific Database Design — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: The application is using a read preference that allows secondary reads. — DocumentDB uses a distributed storage volume with six copies across three Availability Zones. Reads from the primary are strongly consistent by default. However, if the application uses read preferences that allow secondary reads (e.g., 'secondaryPreferred'), then reads may go to replicas which are eventually consistent. The question implies reads are directed to primary, but if the application uses 'secondaryPreferred' and the primary is unavailable, reads may go to secondary. Alternatively, if the application uses a read preference that does not require primary, stale reads can occur. Option D addresses the most common cause: read preference set to allow secondary reads.
What should I do if I get this DBS-C01 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related DBS-C01 NAT questions on configuration and troubleshooting.
Are there clue words in this question I should notice?
Yes — watch for: "most likely", "primary". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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: Jun 20, 2026
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services 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 DBS-C01 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.