SAP-C02 Design for New Solutions Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Use DynamoDB on-demand capacity mode for the table.

  Why this is correct

  DynamoDB on-demand capacity mode automatically scales read and write capacity to handle sudden spikes in traffic without requiring capacity planning. It provides consistent low-latency performance and eliminates the need to manage provisioned throughput, reducing operational overhead. This is ideal for unpredictable workloads.

• ✓

  Configure Lambda provisioned concurrency for the function to reduce cold starts.

  Why this is correct

  Provisioned concurrency pre-initializes a specified number of Lambda execution environments, ensuring that they are ready to respond immediately. This reduces cold start latency and helps maintain consistent low-latency responses during traffic spikes. It also ensures that the function can scale quickly without waiting for new environments to initialize.

• ✗

  Configure Lambda function reserved concurrency to ensure sufficient capacity.

  Why it's wrong here

  Reserved concurrency sets aside a maximum number of concurrent executions for a function, but it does not increase the account's concurrency limit. It can be used to guarantee that a function has capacity, but if the reserved amount is too low, it can cause throttling. To handle spikes, you need to ensure that the account's concurrency limit is high enough, and possibly use provisioned concurrency.

• ✗

  Configure API Gateway with a usage plan and API keys to limit requests per client.

  Why it's wrong here

  Usage plans and API keys are used to throttle and meter access for specific clients, but they do not help handle sudden spikes in traffic. In fact, they can introduce throttling if limits are set too low. The requirement is to avoid throttling errors during spikes, so this approach would be counterproductive unless the limits are very high, which defeats the purpose.

• ✗

  Enable API Gateway caching for the stage to reduce backend requests.

  Why it's wrong here

  API Gateway caching can improve latency for repeated requests, but it does not address sudden spikes in traffic that generate unique requests. Caching is effective for read-heavy workloads with common responses, but for a dynamic application with varied requests, it may not significantly reduce load. It also does not help with DynamoDB capacity or Lambda concurrency.

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