What is distributed caching and how does it improve data processing performance?

Distributed caching stores frequently accessed data across multiple nodes to reduce latency and compute cost.

Distributed caching systems like Redis or Memcached store precomputed or frequently accessed data closer to compute layers. This reduces repeated computation and database load. Caching strategies include LRU eviction, TTL-based expiration, and write-through or write-back patterns. However, cache invalidation is one of the hardest problems in computer science.