SAA-C03 Question 289
Single answerA social media platform is experiencing performance issues due to high database read volumes for frequently accessed user profile data. As the Solutions Architect, you need to design a caching solution to improve performance and reduce database load. The solution must ensure the cached data is automatically invalidated and updated when user profile data changes in the primary database. Which solution should you implement?
- A
Use Amazon ElastiCache with a write-through caching strategy
- B
Use Amazon ElastiCache with a lazy loading caching strategy
- C
Use Amazon ElastiCache with Redis and enable Data Change Notifications (DCN)
- D
Use Amazon ElastiCache with Redis and implement a cache invalidation mechanism triggered by database updates
Show answer and explanation
Correct answer: D
Explanation
The correct solution is to use Amazon ElastiCache with Redis and implement a cache invalidation mechanism triggered by database updates. This design ensures that the cache is consistent with the database, as the invalidation mechanism actively removes or updates outdated cache entries when changes occur in the primary database. Strategies like write-through and lazy loading are not suitable here because they do not address invalidation of stale data. Additionally, while Redis itself supports certain features like Pub/Sub, ElastiCache does not natively support automated notifications for database changes, so a custom invalidation mechanism is required.
- A. Incorrect.
This option is incorrect because a write-through strategy updates the cache only when the database is written to. It does not handle cache invalidation for changes directly made to the database outside the cache.
- B. Incorrect.
This option is incorrect because a lazy loading strategy loads data into the cache only when it is requested and does not ensure automatic invalidation when the database is updated.
- C. Incorrect.
This option is incorrect because while Redis supports features like Pub/Sub, AWS ElastiCache for Redis does not natively support Data Change Notifications (DCN) tied to database updates.
- D. Correct.
This option is correct because using Amazon ElastiCache with Redis and implementing a cache invalidation mechanism triggered by database updates ensures that the cache stays in sync with the primary database when user profile data changes.