Question 1,092 of 1,730
Workload-Specific Database DesigneasyMultiple ChoiceObjective-mapped

DynamoDB for JSON Documents: Low Latency Key-Value Access

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 needs to store JSON documents that are up to 10 KB in size. The documents are accessed by a primary key, and the company requires single-digit millisecond latency. Which database service should be used?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • 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

Amazon DynamoDB

Amazon DynamoDB is the correct choice because it is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale. It natively supports JSON documents up to 400 KB in size (well above the 10 KB requirement) and provides primary key access with consistent low-latency performance, making it ideal for this workload.

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.

  • Amazon Neptune

    Why it's wrong here

    Graph database, not for simple key-value.

  • Amazon DynamoDB

    Why this is correct

    Provides single-digit ms latency for key-value access.

    Clue confirmation

    The clue word "primary" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Amazon S3

    Why it's wrong here

    Higher latency (tens of ms).

  • Amazon RDS for MySQL with JSON data type

    Why it's wrong here

    May have higher latency under load.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may choose Amazon RDS for MySQL with JSON data type because they assume a relational database can handle JSON efficiently, but they overlook the inherent latency overhead of relational engines and the fact that DynamoDB is purpose-built for single-digit millisecond key-value access at any scale.

Detailed technical explanation

How to think about this question

DynamoDB achieves single-digit millisecond latency through its distributed architecture, where data is automatically partitioned across multiple nodes using the primary key as the partition key, and consistent hashing ensures even distribution. The service uses SSDs internally and maintains a write-ahead log for durability, while adaptive capacity handles traffic spikes without manual sharding. In real-world scenarios, DynamoDB is commonly used for session stores, gaming leaderboards, and IoT metadata, where predictable low-latency access to small JSON documents is critical.

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 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.

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 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: Amazon DynamoDB — Amazon DynamoDB is the correct choice because it is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale. It natively supports JSON documents up to 400 KB in size (well above the 10 KB requirement) and provides primary key access with consistent low-latency performance, making it ideal for this workload.

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.

Are there clue words in this question I should notice?

Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

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

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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.