Why SQL Server performance tuning often fails in real environments

This article examines common pitfalls in SQL Server performance tuning, arguing that focusing solely on indexes, statistics, and query plans often misses root causes. It explains how systems evolve over time with changing data volumes, workloads, and concurrency patterns, making initial design assumptions obsolete. Real-world examples include storage bottlenecks, concurrency effects, and interference from other workloads. The article advocates for a broader perspective—stepping back to assess current system usage and context—rather than deeper analysis within the same layer. It emphasizes that effective tuning requires understanding the system's current state, not just applying best practices.