Real-World PostgreSQL: The Write Performance Reality Beyond Benchmarks

Marketing benchmarks dramatically overstate PostgreSQL's real-world write capacity—a single PostgreSQL 18 instance achieves only ~1,875 writes/second with full durability on high-end hardware, far from the advertised 100,000+ inserts/second. Understanding realistic write performance is crucial for mission-critical systems like payments and finance, as synthetic benchmarks can lead teams to make poor architectural decisions. Write performance, not read scaling, represents the true bottleneck even at enormous scale, a limitation that constrains even massive deployments like OpenAI's infrastructure.