Question 193 of 1,730
Workload-Specific Database DesigneasyMultiple SelectObjective-mapped

Quick Answer

The answer is to use strongly consistent reads for inventory data by setting `ConsistentRead=true` on GetItem, Query, or Scan calls, and to implement DynamoDB global tables for user session data to enable low-latency, eventually consistent access across regions. Strongly consistent reads guarantee the most recent write is returned, which is essential for inventory accuracy where stale data could cause overselling, while eventual consistency offers higher throughput and lower latency, making it ideal for session data where slight delays in propagation are acceptable. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of DynamoDB read consistency trade-offs and global table replication, with a common trap being the assumption that global tables provide strong consistency across regions—they do not, as cross-region replication is always eventually consistent. Remember the memory tip: “Inventory needs the latest, sessions can wait—strong for stock, eventual for state.”

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 is designing a highly available e-commerce application using Amazon DynamoDB. The application requires strongly consistent reads for inventory data and eventual consistency for user session data. Which TWO design decisions should the company make?

Question 1easymulti select
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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 strongly consistent reads for the inventory table by setting ConsistentRead=true in the query.

Option D is correct because DynamoDB supports strongly consistent reads by setting the `ConsistentRead=true` parameter in the GetItem, Query, or Scan API calls. This ensures that the application always reads the most recent write, which is critical for inventory data where accuracy is paramount. Strongly consistent reads come at the cost of higher latency and lower throughput compared to eventually consistent reads, but they meet the requirement for inventory 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.

  • Enable DynamoDB Streams on the inventory table to replicate data for disaster recovery.

    Why it's wrong here

    Streams are for change data capture, not for strong consistency.

  • Use DynamoDB Accelerator (DAX) for the inventory table to provide strongly consistent reads.

    Why it's wrong here

    DAX provides eventual consistency, not strong consistency.

  • Use a single DynamoDB table for both inventory and session data with different partition keys.

    Why it's wrong here

    Combining different workloads in one table can lead to performance issues and is not a best practice.

  • Use strongly consistent reads for the inventory table by setting ConsistentRead=true in the query.

    Why this is correct

    ConsistentRead=true ensures strongly consistent reads in DynamoDB.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Use DynamoDB global tables for the user session data to achieve low-latency access across regions.

    Why this is correct

    Global tables provide multi-region replication with eventual consistency, suitable for session data.

    Related concept

    Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume DAX can provide strongly consistent reads because it accelerates read performance, but DAX is an eventually consistent cache and cannot guarantee read-after-write consistency for inventory data.

Detailed technical explanation

How to think about this question

DynamoDB strongly consistent reads read from the leader replica in a multi-AZ deployment, ensuring the latest write is returned, but they have a higher latency (typically single-digit milliseconds) and consume twice the read capacity units (RCUs) as eventually consistent reads. In contrast, eventually consistent reads read from any replica and may return stale data for up to one second. Global tables use multi-region replication with eventual consistency, making them ideal for user session data that can tolerate staleness but require low-latency access across regions.

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.

Related practice questions

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FAQ

Questions learners often ask

What does this DBS-C01 question test?

Workload-Specific Database Design — This question tests Workload-Specific Database Design — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Use strongly consistent reads for the inventory table by setting ConsistentRead=true in the query. — Option D is correct because DynamoDB supports strongly consistent reads by setting the `ConsistentRead=true` parameter in the GetItem, Query, or Scan API calls. This ensures that the application always reads the most recent write, which is critical for inventory data where accuracy is paramount. Strongly consistent reads come at the cost of higher latency and lower throughput compared to eventually consistent reads, but they meet the requirement for inventory consistency.

What should I do if I get this DBS-C01 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.

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Same concept, more angles

1 more ways this is tested on DBS-C01

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 gaming company runs a leaderboard application on Amazon DynamoDB. The application experiences sudden spikes in read traffic during tournaments. The table uses on-demand capacity and the reads are eventually consistent. However, some users report stale data for several seconds. What is the most likely cause?

easy
  • A.The application is using eventually consistent reads.
  • B.The table is using on-demand capacity instead of provisioned capacity.
  • C.The table has a global secondary index (GSI) that is not updated synchronously.
  • D.The read capacity units are insufficient for the traffic spikes.

Why A: The correct answer is A because eventually consistent reads in DynamoDB can return stale data for up to one second under normal conditions, but during sudden spikes in read traffic, the replication lag can extend to several seconds. The application is using eventually consistent reads, which trade immediate consistency for higher throughput and lower latency, making stale data more likely during high-traffic periods like tournaments.

Last reviewed: Jun 24, 2026

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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.