Writing

39 long-form articles on production engineering — how real systems fail, why, and what actually fixed them.

2 articles matching “Eviction”

Picking the Right DBMay 2, 202615 min read

How Redis Actually Deletes Expired Keys — The Lazy + Active Hybrid You Didn't Know About

A senior-engineer walkthrough of how Redis really handles TTLs. Why TTL=0 doesn't free memory. The two strategies — lazy (on-access) and active (the random-sample-and-25%-threshold sampler).

Production IncidentsOct 13, 202628 min read

One Header Was Supposed to Stop Double Charges. Here Are 10 Ways It Didn’t.

A timeout is not a failure. Ten real ways idempotency keys break in payment systems — lost gateway responses, two tabs, racing retries, Redis evictions, expired keys, duplicate webhooks — with the fix for each, ten…