You’ve been hired as a developer to work on an application. This application will be making use of an AWS RDS database and ElastiCache. A requirement is present which states that the cache should always have the most recent data that is present in the database and should not contain stale data.
What strategy for ElastiCache can the developer use to implement this?

Answer options:

A.Lazy loading
B.Write-through
C.Error retries
D.Exponential backoff

Answer - B
The AWS Documentation mentions the following.
Write Through
The write-through strategy adds data or updates data in the cache whenever data is written to the database.
Advantages and Disadvantages of Write Through
Advantages of Write Through
Data in the cache is never stale.
Since the cache data is updated every time it is written to the database, the cache data is always current.
Write penalty vs. Read penalty.
Every write involves two trips:
A write to the cache
A write to the database
Which adds latency to the process. That said, end users are generally more tolerant of latency when updating data than when retrieving data. There is an inherent sense that updates are more work and thus take longer.
Option A is incorrect because lazy loading is a caching strategy that loads data into the cache only when necessary.
Option C and D are incorrect because there are no such strategies.
For more information on different caching mechanisms, please refer to the below link-
https://docs.aws.amazon.com/AmazonElastiCache/latest/mem-ug/Strategies.html