Uber Eats Rebuilds Search Pipeline to Cut End-to-End Latency by 50%

Good reminder that latency wins are usually a pile of boring ones rather than one clever fix. Uber Eats halved end-to-end search latency: ~120ms from deleting low-value retrieval strategies, ~130ms from column-oriented bid data for ads, 100ms+ from splitting ranking hydration out of presentation, 40ms from request hedging. The real change is that they stopped measuring backend API time and started measuring when the first screen renders.