DVA-C02 Question #329: Real Exam Question with Answer & Explanation

Question

A company built an online event platform. For each event, the company organizes quizzes and generates leaderboards that are based on the quiz scores. The company stores the leaderboard data in Amazon DynamoDB and retains the data for 30 days after an event is complete. The company then uses a scheduled job to delete the old leaderboard data. The DynamoDB table is configured with a fixed write capacity. During the months when many events occur, the DynamoDB write API requests are throttled when the scheduled delete job runs. A developer must create a long-term solution that deletes the old leaderboard data and optimizes write throughput. Which solution meets these requirements?

Options

• AConfigure a TTL attribute for the leaderboard data.
• BUse DynamoDB Streams to schedule and delete the leaderboard data.
• CUse AWS Step Functions to schedule and delete the leaderboard data.
• DSet a higher write capacity when the scheduled delete job runs.

Explanation

Option A is correct because DynamoDB's Time To Live (TTL) feature automatically deletes expired items in the background without consuming write capacity units - it's a native, zero-cost deletion mechanism that completely sidesteps throttling issues.

Why the distractors fail:

• B (DynamoDB Streams): Streams capture change events for processing; they don't schedule deletions, and any delete you trigger from a stream still consumes write capacity.
• C (Step Functions): Orchestrating deletes via Step Functions still issues standard DeleteItem API calls that consume write capacity - it just adds orchestration overhead without solving the throttling root cause.
• D (Higher write capacity): Manually scaling capacity before the job runs is a reactive, operational workaround, not a long-term solution - it still wastes capacity and requires ongoing maintenance.

Memory tip: Think of TTL as "self-destructing data" - you stamp an expiry date on the item at write time, and DynamoDB handles cleanup for free, off your capacity budget. Any solution that still calls a Delete API will still burn WCUs; TTL bypasses that entirely.

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