Key points

• Use cache-aside or another suitable application pattern around a durable source of truth.
• Keys, TTL, invalidation, eviction, failure behavior, and tenant scope determine correctness.
• A high hit rate helps only when reused values remain authorized and fresh enough.

Best-known use cases

• Reduce repeated expensive database reads.
• Store reusable transient application results with bounded freshness.

What candidates often confuse it with

• ElastiCache accelerates access; DynamoDB, Aurora, or RDS normally remains the durable source.
• Application caches differ from CloudFront edge response caches in location, objects cached, and cache keys.

Key takeaway

Choose ElastiCache when repeated application reads justify an explicit cache-consistency design.

Related services

• Amazon DynamoDB
• Amazon Aurora
• Amazon RDS
• Amazon CloudFront

Relevant exam tasks

• D1.3 — Use data stores in application development
• 1.3.8 — Use data caching services
• D4.3 — Optimize applications by using AWS services and features
• 4.3.6 — Implement application-level caching to improve performance

Learn more

• Amazon ElastiCache