By Sanjeeva Kumar | Senior Oracle DBA & Database ArchitectPublished: February 2026 | Reading time: 8 minutes The Scaling Advice That’s Costing You Millions OpenAI is running 800 million ChatGPT users on unsharded PostgreSQL. One primary writer per cluster. 50+ read replicas. No Cassandra. No sharding. Just PostgreSQL — properly governed. Sound familiar? It shouldn’t. Read more about PostgreSQL Scaling: What OpenAI Proved Wrong at 800M Users[…]