TechEmpower: Axum ~400K RPS optimized, ~43K with idiomatic SQLx (not 200K)

TechEmpower benchmarks: Axum reaches ~400K RPS for simple PostgreSQL queries using shared-nothing architecture (one Tokio runtime per thread). However, "most idiomatic" Axum with standard SQLx connection pooling drops to ~43K RPS — underperforming Go, PHP, and Java. The 200K+ claim is realistic only for lightweight handlers without DB access.