Introduction to SQL Tuning

Introduction

What kind of solid approach can you take when trying to tune a problem SQL statement ?

How do you know if the optimizer chose the right execution path? If the execution path is wrong how do you find the right one?

The goal of the method outlined here is to be able to look at a query and apply a methodology to understand as well as identify the best execution paths through a query.

The above graphic represents a query (in gray text) two with two possible execution plans being compared side by side. The textual approach on top has been the classic method. The method on bottom is the method introduced here using graphics and a step by step methodology.