Question 386 of 1,616
Development with AWS ServiceshardMultiple ChoiceObjective-mapped

DynamoDB Capacity Mode for Cost Optimization: On-Demand vs Provisioned

This DVA-C02 practice question tests your understanding of development with aws services. 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 developer is using Amazon DynamoDB to store session data for a web application. The application reads and writes a single item per user session. The traffic pattern shows occasional spikes. The developer wants to minimize read and write costs. Which DynamoDB capacity mode should the developer choose?

Clue words in this question

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

  • Clue: "minimum / minimize"

    Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

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

On-demand capacity

On-demand capacity mode is ideal for unpredictable traffic patterns with occasional spikes because it automatically scales read and write throughput based on actual usage, charging only for consumed operations. Since the application reads and writes a single item per session and experiences spikes, on-demand eliminates the need to provision for peak capacity, minimizing costs compared to over-provisioning.

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.

  • Reserved capacity

    Why it's wrong here

    Requires upfront commitment, not suitable for variable traffic.

  • On-demand capacity

    Why this is correct

    Pay-per-request, handles spikes without throttling.

    Clue confirmation

    The clue word "minimum / minimize" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Provisioned capacity with manual scaling

    Why it's wrong here

    Manual scaling is not responsive to spikes.

  • Provisioned capacity with auto scaling

    Why it's wrong here

    Auto scaling may not react fast enough for spikes.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may confuse 'Reserved capacity' with a valid DynamoDB option or assume that auto scaling (Option D) is always the cheapest for variable traffic, but on-demand is specifically designed for unpredictable spikes to avoid over-provisioning costs and throttling.

Detailed technical explanation

How to think about this question

DynamoDB on-demand mode uses a per-request pricing model where you pay only for the reads and writes you perform, with no minimum capacity and automatic scaling up to your account's default throughput limits (e.g., 40,000 read and 40,000 write request units per table). Under the hood, on-demand tables leverage a distributed adaptive capacity mechanism that instantly absorbs traffic bursts without throttling, making it cost-effective for workloads with unpredictable spikes, though it can be more expensive than provisioned for steady-state traffic due to higher per-unit costs.

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.

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FAQ

Questions learners often ask

What does this DVA-C02 question test?

Development with AWS Services — This question tests Development with AWS Services — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: On-demand capacity — On-demand capacity mode is ideal for unpredictable traffic patterns with occasional spikes because it automatically scales read and write throughput based on actual usage, charging only for consumed operations. Since the application reads and writes a single item per session and experiences spikes, on-demand eliminates the need to provision for peak capacity, minimizing costs compared to over-provisioning.

What should I do if I get this DVA-C02 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: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.

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 DVA-C02 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 DVA-C02 exam.