This is not your typical SQL tuning talk. We’re deep diving --> beyond basic indexing tips --> into how modern relational databases actually parse, plan, and execute your queries.

- Do you know how SQL is parsed?
- Why does the optimizer sometimes pick the “wrong” plan?

Along the way we'll stumble upon subtle ways things can go wrong!

- How can correlated subqueries sabotage execution?
- When do query rewrites go sideways?

From PostgreSQL's bitmap scans to SQL Server's parallelism quirks to MySQL's index merge madness - learn to spot performance killers and know exactly which optimization lever to pull.

If you've ever stared at a slow query wondering "what exactly is the database _doing_ right now?", come find the answer in this talk. Packed with example code, edge cases, and real-world pathologies, it’s everything you’ve ever wanted to know about SQL performance (and probably a few things you didn’t - but should!).