LRU Cache

Definitions

1. Least Recently Used cache — a fixed-size cache that evicts the least recently accessed item when full. Implemented with a hash map (O(1) lookup) and a doubly-linked list (O(1) move-to-front and eviction). The most common cache eviction policy, used in CPU caches, database buffer pools, and application caches.

   In plain English: A cache that automatically removes the least recently used items when it runs out of space.

   Example: "The API response cache is an LRU with 1,000 entries — popular endpoints stay cached while rarely-accessed ones get evicted."

Related Terms

• Hash Table
• Bloom Filter
• Ring Buffer
• Stale-While-Revalidate
• ETag
• Cache Stampede
• Disk Cache
• Inline Cache
• LRU
• Memcached
• Query Cache
• Turborepo
• Write Back
• Write Through