DynamoDB capacity modes (on-demand, provisioned) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding DynamoDB On-Demand Capacity Mode

Which statement correctly describes the behavior of DynamoDB when using the on-demand capacity mode?

A You pay a flat monthly fee for unlimited read and write operations regardless of usage.

B You must specify read and write capacity units in advance, and you pay for the provisioned capacity regardless of usage.

C You are limited to a fixed number of read and write operations per second, which cannot be changed after table creation.

D DynamoDB automatically scales capacity to handle incoming requests and you pay only for the read and write requests you use.

💡 Hint

Think about how DynamoDB handles sudden traffic spikes without manual capacity changes.

On-demand mode lets DynamoDB automatically adjust capacity to your workload. You pay only for the requests you make, without specifying capacity units upfront.

🧠 Conceptual

intermediate

Provisioned Capacity Mode Characteristics

Which of the following is true about DynamoDB's provisioned capacity mode?

A You pay only for the read and write requests you use, with no need to specify capacity units.

B You specify the number of read and write capacity units, and you are billed for these units whether used or not.

C Provisioned capacity mode automatically scales capacity based on traffic without any manual input.

D Provisioned capacity mode is only available for global tables and not for single-region tables.

💡 Hint

Consider how billing works when you reserve capacity in advance.

Provisioned mode requires you to set capacity units ahead of time. You pay for these units regardless of actual usage, which can save money if traffic is predictable.

❓ Architecture

advanced

Choosing Capacity Mode for a Variable Traffic Application

You have a new application with unpredictable traffic that can spike suddenly. Which DynamoDB capacity mode should you choose to minimize operational overhead and avoid throttling?

A On-demand capacity mode to automatically handle traffic spikes without manual intervention.

B Provisioned capacity mode with manual scaling to handle peak traffic.

C Provisioned capacity mode with auto-scaling enabled to adjust capacity automatically.

D On-demand capacity mode with reserved capacity units to reduce costs.

💡 Hint

Think about which mode best handles sudden unpredictable traffic without manual changes.

On-demand mode is designed for unpredictable workloads and automatically adjusts capacity to avoid throttling without manual scaling.

❓ security

advanced

Impact of Capacity Mode on Security and Access Control

How does choosing between on-demand and provisioned capacity modes affect the security and access control of a DynamoDB table?

A Capacity mode choice does not affect security or access control; IAM policies and encryption work the same for both modes.

B Provisioned mode requires additional encryption settings for security compared to on-demand mode.

C On-demand mode disables IAM policies, so access control is managed differently.

D On-demand mode automatically enables public read access for faster scaling.

💡 Hint

Consider if capacity mode changes how you manage permissions or encryption.

Security features like IAM policies and encryption are independent of capacity mode. Both modes support the same security controls.

❓ service_behavior

expert

Billing Behavior Differences Between Capacity Modes

Which billing behavior correctly distinguishes DynamoDB's on-demand capacity mode from provisioned capacity mode?

A On-demand mode charges a fixed monthly fee plus a small fee per request, while provisioned mode charges only per request.

B On-demand mode charges based on data storage size only, ignoring read/write requests.

C Provisioned mode charges for the capacity units you specify regardless of usage, while on-demand mode charges only for the actual read and write requests made.

D Both modes charge the same way, but on-demand mode offers discounts for reserved capacity.

💡 Hint

Think about how billing differs when capacity is reserved versus when it is flexible.

Provisioned mode bills for reserved capacity units regardless of usage, while on-demand bills only for actual requests, making it more flexible but sometimes more costly for steady workloads.