SQLBits 2020
Execution plans ... where do I start?
Execution plans are key to understanding bad query performance. But they can be overwhelming to the new user. Where to start? This session will show the basics!
SQL (the language) is not a third generation language, where the developer tells the computer every step it needs to take. It is a declarative language that specifies the required results. SQL Server itself will figure out what steps it takes to get to those results. Most of the time, that works very well.
But sometimes it doesn't. Sometimes a query takes too much time. You need to find out why, so you can fix it. That's where the execution plan comes in. In the execution plan, SQL Server exposes exactly which steps it took for your query, so you can see why it's slow.
However, execution plans can be daunting to the uninitiated. Especially for complex queries. Where do you even start?
In this session you will learn how to obtain execution plans. and how to start reading and understanding them.