A developer has built a market application that stores pricing data in Amazon DynamoDB with Amazon ElastiCache in front.The prices of items in the market change frequently.Sellers have begun complaining that, after they update the price of an item, the price does not actually change in the product listing.
What could be causing this issue?
The cache is not being invalidated when the price of the item is changed
The price of the item is being retrieved using a write-through ElastiCache cluster
The DynamoDB table was provisioned with insufficient read capacity
The DynamoDB table was provisioned with insufficient write capacity
Explanations:
The cache is not being invalidated after the price change, so the stale cached data is returned.
A write-through cache would update the cache on writes to DynamoDB, but this isn’t the problem here.
Insufficient read capacity would affect reads from DynamoDB, not cache synchronization.
Insufficient write capacity would cause failures during writes, but not cache stale data.
I measure that the answer is:
The cache is not being invalidated when the price of the item is changed