AWS Certified Solutions Architect – Associate (SAA-C02) — Question 303

A company is planning to use an Amazon DynamoDB table for data storage. The company is concerned about cost optimization. The table will not be used on most mornings in the evenings, the read and write traffic will often be unpredictable. When traffic spikes occur they will happen very quickly.
What should a solutions architect recommend?

Answer options

• A. Create a DynamoDB table in on-demand capacity mode.
• B. Create a DynamoDB table with a global secondary Index.
• C. Create a DynamoDB table with provisioned capacity and auto scaling.
• D. Create a DynamoDB table in provisioned capacity mode, and configure it as a global table.

Correct answer: A

Explanation

Amazon DynamoDB on-demand capacity mode is the most cost-effective option for unpredictable workloads with sudden spikes because it scales instantly to meet demand and charges only for the resources consumed. While provisioned capacity with auto scaling can adjust to traffic, it cannot react quickly enough to instantaneous spikes and still incurs costs during idle morning hours. Global tables and global secondary indexes are replication and querying features that do not address the rapid scaling and cost-optimization requirements of this workload.