Does Postgres Scale?

PostgreSQL demonstrates exceptional scalability for workflow execution, sustaining 144K writes per second (43K workflows/second) on a single server—sufficient for 4 billion workflows daily. The WAL (Write-Ahead Log) flushing mechanism, not CPU or I/O resources, is the primary bottleneck, meaning PostgreSQL's write performance is fundamentally limited by transaction commit serialization rather than hardware constraints. This validates PostgreSQL as a viable enterprise-grade backend for durable workflow systems, potentially reducing infrastructure complexity and costs compared to specialized workflow engines.