Inside the SQL Server Query Optimizer - part 2 All about the Simplification
Hi guys, I am back! After the introduction done in the previous article , today we talk about the simplication step of the Query Optimizer. In my opinion, knowing what types of optimization SQL Server might apply is very important in order to write a Query that run Quickly! So, are you ready for the second part of this exciting journey to discover the Query Optimizer? Ready? Go! The Simplification Let now start speaking about the Simplification phase. Simplification is the first step of the optimization pipeline. It's an important step because during this phase the optimizer try to modify the logical tree in order to remove redundancies. Optimizer try also to change the order of the logical operation in order to facilitate later step . We can split the simplification phase into various sub phases that are: Constant Folding Domain simplification Predicate push-down Join simplification Contradiction detection The constant folding During this phase SQL s...