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.

• ✗

  Add a secondary index

  Why it's wrong here

  Adding a secondary index, whether a Global Secondary Index (GSI) or Local Secondary Index (LSI), does not increase the provisioned throughput capacity of the base table itself. While indexes offer alternative query patterns, they consume their own dedicated read and write capacity units (RCUs/WCUs) and do not directly alleviate throttling issues occurring on the primary table. In fact, writes to the base table are asynchronously replicated to GSIs, consuming additional write capacity on the index, which could potentially exacerbate overall write capacity issues if not properly provisioned.

• ✗

  Decrease the provisioned write capacity

  Why it's wrong here

  Decreasing the provisioned write capacity would directly reduce the number of write capacity units (WCUs) available to the DynamoDB table. If the application is already experiencing throttling, which indicates that the current capacity is insufficient to handle the incoming write requests, further reducing this capacity would only intensify the throttling events and severely degrade application performance. This action would make the existing problem significantly worse, not better.

• ✓

  Enable DynamoDB Auto Scaling

  Why this is correct

  Enabling DynamoDB Auto Scaling, powered by AWS Application Auto Scaling, is the most effective solution for preventing throttling due to fluctuating workloads. Auto Scaling dynamically adjusts the table's provisioned read and write capacity units (RCUs/WCUs) up or down in response to actual traffic patterns and utilization metrics. By automatically increasing capacity during peak demand and decreasing it during lulls, it ensures sufficient throughput to avoid throttling while optimizing costs.

• ✗

  Increase the provisioned read capacity only

  Why it's wrong here

  Increasing only the provisioned read capacity units (RCUs) would not resolve throttling issues if the underlying problem is insufficient write capacity. DynamoDB throttling occurs independently for reads and writes; a `ProvisionedThroughputExceededException` for a write operation indicates a lack of WCUs. Therefore, if the application is experiencing write-related throttling, increasing read capacity would have no impact on alleviating the write-related bottlenecks, leaving the core issue unaddressed.

Go deeper

Related to this question