1Z0-997-25 Question 95
Single answerYour e-commerce application on Oracle Cloud Infrastructure (OCI) frequently handles thousands of reads per second and updates product inventory data several times per minute. To improve performance and reduce load on your back-end database, you plan to use OCI Cache. Which caching approach ensures data consistency while maintaining high performance in this scenario?
- A
Use a write-behind pattern to asynchronously update the database from OCI Cache
- B
Use a read-through caching pattern with periodic cache refresh intervals
- C
Use a cache-aside approach, ensuring the application explicitly invalidates or updates cached data after writes
- D
Rely solely on the default pass-through approach without additional cache invalidation steps
Show answer and explanation
Correct answer: C
Explanation
Using a cache-aside pattern is a commonly endorsed practice for data that requires careful consistency management while also benefiting from cached reads. According to OCI best practices, after updating the database, you should explicitly invalidate or refresh cache entries to keep data accurate. This ensures stale data is not served to end-users while still offloading the majority of read traffic to the in-memory cache, achieving both performance and consistency for high-concurrency use cases. Refer to the latest OCI Cache documentation for further guidelines on implementing cache-aside patterns and appropriate TTL settings.
- A. Incorrect.
Option 1 (Write-behind): In a write-behind pattern, updates to the database happen asynchronously after writing to the cache. This can improve write performance but risks data inconsistency if the cache fails before the database is updated. It also complicates transaction management for inventory data.
- B. Incorrect.
Option 2 (Read-through with periodic refresh): Read-through automatically loads data into the cache on a miss, which can reduce latency for reads. However, relying on fixed refresh intervals can still leave data stale if changes happen in rapid sequence�a common scenario with inventory updates.
- C. Correct.
Option 3 (Cache-aside with explicit invalidation/update): This is correct. In the cache-aside pattern, the application directly interacts with the cache and database. After updating the database, the application either invalidates or updates the relevant cache entries to ensure data consistency. This approach is recommended for frequently updated data like inventory, as it strikes a balance between performance and consistency.
- D. Incorrect.
Option 4 (No invalidation): Relying on a pass-through or default approach without cache invalidation can cause stale data to linger in the cache for an unknown period, resulting in inaccurate inventory levels and potentially inconsistent user experiences.