DVA-C02 Development with AWS Services 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.

• ✓

  Configure DynamoDB auto scaling for the table

  Why this is correct

  DynamoDB auto scaling dynamically adjusts the provisioned read and write capacity units (RCUs/WCUs) for a table or global secondary index based on actual traffic patterns. By automatically increasing capacity during peak loads and decreasing it during lulls, auto scaling ensures that the table has sufficient throughput to handle incoming requests, effectively preventing throttling errors caused by exceeding provisioned limits.

• ✓

  Implement exponential backoff and retry in the application code

  Why this is correct

  Implementing exponential backoff and retry in the application code is a crucial client-side strategy to gracefully handle transient throttling errors from DynamoDB. When a request is throttled, the application waits for an increasing duration before retrying, spreading the load over time and reducing the immediate request rate. This approach prevents a flood of immediate retries from exacerbating the throttling issue, allowing the table's capacity to recover.

• ✗

  Use a global secondary index with a different partition key

  Why it's wrong here

  While a Global Secondary Index (GSI) allows for querying data using different attributes as a partition key, it operates with its own independent provisioned throughput capacity, separate from the base table. Using a GSI does not prevent throttling on the *base table* itself; if the primary table's access patterns exceed its provisioned RCUs or WCUs, it will still be throttled, irrespective of any GSIs.

• ✗

  Use strongly consistent reads for all queries

  Why it's wrong here

  Using strongly consistent reads for all queries is counterproductive for preventing throttling, as they consume twice the read capacity units (RCUs) compared to eventually consistent reads for the same amount of data. This increased RCU consumption means that the table will hit its provisioned throughput limits much faster, thereby *increasing* the likelihood and frequency of throttling errors rather than mitigating them.

• ✓

  Enable DynamoDB Accelerator (DAX) for caching

  Why this is correct

  Enabling DynamoDB Accelerator (DAX) provides an in-memory cache that sits in front of your DynamoDB tables, significantly reducing the read load on the underlying database. DAX intercepts read requests, serving cached data with microsecond response times whenever possible, which drastically decreases the number of requests that actually reach the DynamoDB table. This reduction in direct table reads effectively lowers the required read capacity, making throttling less likely.

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