Soru

Zorluk: ZorOptimizing Performance with Caching and DAX

A developer is optimizing a reporting service that retrieves product catalog listings from an Amazon DynamoDB table. The service frequently executes the same Query operations to retrieve items by category. To reduce latency, the developer deploys an Amazon DynamoDB Accelerator (DAX) cluster and updates the application code to use the DAX SDK client. While individual GetItem operations now exhibit sub-millisecond latency, the Query operations continue to experience high latency and consume the table's Provisioned Throughput. Which modification should the developer make to ensure the Query operations are successfully cached by DAX?

  1. Configure the Query operations in the application code to perform eventually consistent reads by setting the ConsistentRead parameter to false.Cevap
  2. B
    Replace the Query operations in the application code with Scan operations to allow the results to be cached within the DAX item cache.
  3. C
    Increase the Provisioned Read Capacity Units (RCUs) of the DynamoDB table to prevent DAX from bypassing the cache when query volumes spike.
  4. D
    Initialize the DAX SDK client by hardcoding the access key and secret key of an IAM user that has DynamoDB read permissions.

Cevap

Configure the Query operations in the application code to perform eventually consistent reads by setting the ConsistentRead parameter to false.
DAX does not cache strongly consistent reads (such as Query or Scan operations where ConsistentRead is set to true). These requests are passed through directly to the underlying DynamoDB table. To utilize the DAX query cache, the developer must configure the client to perform eventually consistent reads by setting ConsistentRead to false.

Adım Adım Çözüm

1
Analyze the DAX caching behavior for strongly consistent vs eventually consistent reads.
Identify that DAX does not cache strongly consistent reads (where ConsistentRead is set to true) and passes them through to DynamoDB.
To understand why Query operations are bypassing the DAX cache and consuming DynamoDB RCUs.
2
Change the configuration of the Query operation in the application code.
Set the ConsistentRead parameter to false for the query calls.
This allows DAX to cache the results of the Query operations in its query cache, serving subsequent identical requests from memory.

Anahtar Kavram

DAX Query Cache Consistency Requirements
Bu soruyu puanla