Book Image

SQL Server 2017 Developer's Guide

Book Image

SQL Server 2017 Developer's Guide

Overview of this book

Microsoft SQL Server 2017 is a milestone in Microsoft's data platform timeline, as it brings in the power of R and Python for machine learning and containerization-based deployment on Windows and Linux. This book prepares you for advanced topics by starting with a quick introduction to SQL Server 2017's new features. Then, it introduces you to enhancements in the Transact-SQL language and new database engine capabilities before switching to a different technology: JSON support. You will take a look at the security enhancements and temporal tables. Furthermore, the book focuses on implementing advanced topics, including Query Store, columnstore indexes, and In-Memory OLTP. Toward the end of the book, you'll be introduced to R and how to use the R language with Transact-SQL for data exploration and analysis. You'll also learn to integrate Python code into SQL Server and graph database implementations as well as the deployment options on Linux and SQL Server in containers for development and testing. By the end of this book, you will be armed to design efficient, high-performance database applications without any hassle.
Table of Contents (25 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Free Chapter
1
Introduction to SQL Server 2017
Index

Adaptive query processing in SQL Server 2017


SQL Server Query Optimizer performs a very good job in the generation of execution plans. However, due to query complexity, skewed data distribution, suboptimal database design and badly written code, it makes sometimes very bad cardinality estimations that lead to slow performing execution plans. Because of wrong estimations, it can choose inappropriate plan operators (for instance Nested Loop Join instead of Hash Join), or a query can get significantly more or less memory granted for the execution than it is required. Sometimes, it simply assumes a fixed cardinality of 100 or 1.

SQL Server 2017 introduces query processing improvements that will adapt optimization and address the aforementioned issues. These improvements break the pipeline between query optimization and execution. For the first time, SQL Server 2017 executes a part of the query during the optimization process (without the OPTION (RECOMPILE) clause) and replaces a part of the execution...