// ROUTE_TRANSITION_SYS :: BLOG/REDIS CACHING PATTERNS LRU CACHE STAMPEDE/
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// KROMA CODE BLOG :: BACKEND ARCHITECTURE
Redis Caching Patterns: Preventing Cache Stampedes, Thundering Herds, and Key Eviction
Shishir Singh• 10 min read•July 21, 2026
💡 ARTICLE EXECUTIVE SUMMARY: "What happens when a cached product page expires under 50,000 concurrent requests? Learn how probabilistic early expiration and distributed Redis locks prevent database crashes."
1. The Cache Stampede Problem
A cache stampede (or thundering herd) occurs when a heavily accessed cached key expires. Thousands of concurrent incoming user requests find a cache miss simultaneously and hit the underlying PostgreSQL database at the exact same instant, causing query timeouts and complete database failure.
2. XFetch Algorithm: Probabilistic Early Expiration
Instead of hard key expiration, production systems use the XFetch algorithm to recompute cache keys in the background before they expire, ensuring 0% cache misses during traffic spikes.
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Backend APIs & Database Architecture // FEATURED CASE STUDY
SGMS World Enterprise System Written by Shishir Singh (Founding Engineer at Kroma Code, Lucknow)
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