Two regions race the last seat.

A section with one seat left, two fans on two regional endpoints, the same instant. Flip between the naive path and Dhamana’s guarded path and watch what the database does at commit — then run the flash-drop load test to see it scale.

Why it survives a real drop

A single hot seat counter collapses under a stampede (every buy conflicts on one row). Sharding the section into N warm buckets spreads the writes — same zero-oversell guarantee, far more throughput. Fire 120 concurrent buyers at a 1,000-seat section across bucket counts: