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Difficulty: MediumResolving DynamoDB Throttling and Key Distribution Issues

A smart grid monitoring application named 'GridMonitor' collects electricity usage data from regional smart meters. The application writes these metrics directly to an Amazon DynamoDB table configured with provisioned write capacity. During daily peak hours, the application occasionally receives ProvisionedThroughputExceededException errors, leading to immediate transaction failures. A review of Amazon CloudWatch metrics shows that the overall write throughput is well below the provisioned capacity limit, but the application's SDK client configuration has retries disabled. Which action should the developer take to resolve these transient write errors in the most cost-effective manner?

  1. A
    Replace the current write logic with a Scan operation to locate and re-process failed writes.
  2. B
    Increase the visibility timeout of the SQS queue feeding the ingestion service to handle throttled requests.
  3. Configure the SDK client to use exponential backoff and jitter for retries.Answer
  4. D
    Hardcode the AWS credentials directly in the initialization parameters of the SDK client.

Answer

Configure the SDK client to use exponential backoff and jitter for retries.
Implementing exponential backoff and jitter in the SDK client allows the application to automatically retry failed requests after progressively longer intervals with randomized variation (jitter). This spreads out the retries to avoid overwhelming the database during transient spikes in traffic, making it the most cost-effective solution as it does not require provisioning extra database capacity or changing the architecture.

Step-by-Step Solution

1
Analyze the error metrics and application configuration.
Identify that the ProvisionedThroughputExceededException is occurring despite the table's total throughput being sufficient, indicating transient spikes, and that the SDK has retries disabled.
To pinpoint whether the issue requires scaling the table or modifying client-side retry behaviors.
2
Select a retry strategy that spreads requests over time.
Configure the SDK client with exponential backoff and jitter.
Exponential backoff increases wait times between consecutive retries, while jitter introduces randomness to prevent retry collisions from multiple client instances.
3
Deploy the updated application configuration and verify the error rate.
Transient spikes are handled gracefully by SDK retries, eliminating immediate write failures without increasing DynamoDB capacity costs.
To confirm that the solution handles the micro-bursts of traffic effectively.

Key Concept

Configuring SDK client retry policy with exponential backoff and jitter to mitigate transient DynamoDB throttling exceptions.
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Topics

Resolving DynamoDB Throttling and Key Distribution Issues