Cache Eviction Policies: LRU, LFU, FIFO, & TTL
Manage finite memory capacity: Least Recently Used (LRU), Least Frequently Used (LFU), First In First Out (FIFO), and Time-to-Live (TTL).
01.1. Why Cache Eviction Policies are Necessary
Cache memory (DRAM) is fundamentally finite and significantly more expensive per gigabyte than SSD storage. When a cache server reaches its configured memory limit (maxmemory in Redis, e.g., 16GB), it cannot allocate memory for new keys without discarding existing data.
An Eviction Policy is the algorithmic decision framework that determines which key should be evicted to free up space while preserving the highest possible overall Cache Hit Ratio.
LRU vs LFU Eviction Mechanics 🔄
LRU vs LFU Eviction Mechanics 🔄
Doubly Linked List + Hash Map (LRU) vs Frequency Min-Heap (LFU).
Unlock Topic #102: Cache Eviction Policies: LRU, LFU, FIFO, & TTL
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