Ever wonder how an update query actually works? What are all those strange operators in the query tree? How do I tell if an update query is performing well? In this talk, Conor will go into depth about how the Query Optimizer builds plans for Insert/Update/Delete/Merge queries, including understanding operators like common subexpression spools and split/sort/collapse and optimizations like narrow vs. wide plans, non-updating updates, prefetch optimizations, the “with outputs” feature, and how we can maintain indexed views incrementally.