A cache has 95% hit rate. A new feature doubles the number of cacheable objects. What happens to hit rate and how do you address it?

Which caching pattern checks the cache first, then the database on miss, then populates the cache?

Write-through caching always writes to both cache and database simultaneously.

Which Redis data structure is best for implementing a real-time leaderboard?

What is a cache stampede?

Explain negative caching and when to use it.