Database Bottlenecks Nobody Talks About: Optimizing SQL Queries Beyond Indexing

Every performance guide starts the same way. "Add an index." And yes, indexes matter. But I've spent years fixing production databases, and here's the truth: indexing is the easy 20%. The hard 80% is everything nobody writes blog posts about.

I once spent three days chasing a query that had a perfect index. The index wasn't the problem. The problem was that the database's own statistics were lying to it.