<b>This week in caching: stopping the thundering herd</b>

<b>This week in caching: stopping the thundering herd</b>
Three reads on what happens the instant a hot key expires.
— <b>probabilistic early expiration</b> — the XFetch algorithm (Vattani et al.) refreshes a key slightly before TTL with rising probability, so one request rebuilds while others serve stale. Elegant, ~10 lines.
— <b>lock-based regeneration</b> — Laravel's <code>Cache::lock()</code> and Redis SETNX patterns: first request rebuilds, rest wait or serve old.
— <b>request coalescing at the edge</b> — Cloudflare's and Varnish's built-in collapsing means 10k simultaneous misses hit origin once.
<b>Bookmark:</b> the original XFetch paper — short, and the probability curve is genuinely clever.