What should the database specialist review first to improve the utility of DAX?
The DynamoDB ConsumedReadCapacityUnits metric
The trust relationship to perform the DynamoDB API calls
The DAX cluster’s TTL setting
The validity of customer-specified AWS Key Management Service (AWS KMS) keys for DAX encryption at rest
Explanations:
The DynamoDB ConsumedReadCapacityUnits metric tracks the capacity usage, not cache hits or misses in DAX. It doesn’t provide direct insight into why DAX cache isn’t being used effectively.
The trust relationship is related to AWS IAM permissions and wouldn’t directly affect DAX cache performance. DAX operates within the same IAM policies, so this wouldn’t impact cache usage.
The TTL (Time-to-Live) setting controls how long cached data is kept in DAX before it expires. If the TTL is too short, it may result in frequent cache misses. Adjusting TTL can improve cache hit rates.
AWS KMS keys are used for encryption at rest in DAX. While important for security, the validity of KMS keys does not directly affect DAX cache usage or performance.
I reckon the answer is:
The DAX cluster’s TTL setting