Caching Use Cases

• Lazy Loading: save/update data in cache when reading from db
• Write Through: save/update data in cache when writing to db
• Session Store: store temporarily using TTL features

DB Cache

• Cache hit: cache is in elasticache
• Cache miss: cache is not present in elasticache
• Relieve load from the RDS
• Cache must have an invalidation strategy to make sure it has the most recent data

User Session Store

• Helps the applications become stateless
• The app no longer stores the user session locally, but saves it in elasticache

Gaming Leaderboard

• Redis Sorted Sets guarantee both uniqueness and ordering
• Each time a new element is added, it's added in the correct order