Page 2 of 2
One ticket left, two thumbs on the Buy button. Whether you call the bug a lost update or a write skew depends on how you modelled the data, and the fix depends on the name. A walk through ACID's fine print, read committed, snapshot isolation, and four ways to fix a counter, with Postgres SQL you can run.
Posting one tweet sounds light, but behind it can sit thirty million writes. Load parameters, two ways to build a timeline, why the celebrity breaks one of them, the hybrid that fixes it, and why a 500-person group chat and a million-person channel want opposite designs. First of a series of notes from reading DDIA.
Ten API pods, one shared budget per client, and a hard rule that the limiter must never become the outage. Choosing an algorithm, making it atomic in Redis with one Lua script, and deciding what to do when Redis itself is gone.
