Nikhlesh Patle | Technical Architect - 10+ Years on Instagram: "🧹 Mastering Login Slowness — 20M Users, Still Lightning Fast ⚡🧠 —————————————— 🧩 1️⃣ What It Means 🐌 20M-row User Table = Login query becomes slow 🔍 Caused by missing indexes, wide tables, expensive lookups 🎯 Goal: Make login O(log n), not O(n) —————————————— 🧱 2️⃣ The Flow 1️⃣ Login hits DB using email/username 2️⃣ DB performs slow lookup (seq scan / wide table scan) 3️⃣ App waits → timeouts, latency spikes 4️⃣ Fix = index +