8.9 Matching Flow and Driver Reservations

Finding candidates is half of matching. The previous lesson built the live index for Lahore: drivers in drivers:{lahore}:economy, written with GEOADD every 4 seconds and searched with GEOSEARCH in widening rings. A last-seen sorted set then drops any driver who has sent no update for more than 15 seconds.

This lesson turns those candidates into one assigned trip. It covers the matching flow, the reservation that keeps a driver from receiving two offers at once, the index choices used beyond Redis geo at very large scale, and how the system behaves when parts of it fail.