LRU

Definitions

1. Least Recently Used — a cache eviction policy that discards the entry that has gone the longest without being accessed. Typically implemented with a hash map plus a doubly-linked list to achieve O(1) get, put, and eviction.

   In plain English: A rule for what to throw out of a cache when it gets full: get rid of whatever hasn't been used in the longest time.

   Example: "Our LRU cache holds the last 10,000 user sessions; anything untouched for long enough gets evicted when we hit the limit."

Related Terms

• Mapping
• STL
• Weak Reference
• Memoization
• TTL
• LRU Cache
• Stale-While-Revalidate
• Cache Eviction