DB Locking 101 for Serverless Devs

A flash sale goes live on a popular booking platform. Fifty dollars off the Friday evening flight from New York to London. Within seconds, a thousand Lambdas wake up and each one runs: UPDATE flight_inventory SET seats_available = seats_available - 1 WHERE flight_id = 'NYC-LON-FRI' AND fare_class = 'Y' ; Your p99 latency jumps from 50ms to 30 seconds. No code changed. No deploy. CPU is fine. Connections look healthy-ish. What happened? The answer is locks . If your mental model of database locki