Book Image

Teradata Cookbook

By : Abhinav Khandelwal, Viswanath Kasi, Rajsekhar Bhamidipati
Book Image

Teradata Cookbook

By: Abhinav Khandelwal, Viswanath Kasi, Rajsekhar Bhamidipati

Overview of this book

Teradata is an enterprise software company that develops and sells its eponymous relational database management system (RDBMS), which is considered to be a leading data warehousing solutions and provides data management solutions for analytics. This book will help you get all the practical information you need for the creation and implementation of your data warehousing solution using Teradata. The book begins with recipes on quickly setting up a development environment so you can work with different types of data structuring and manipulation function. You will tackle all problems related to efficient querying, stored procedure searching, and navigation techniques. Additionally, you’ll master various administrative tasks such as user and security management, workload management, high availability, performance tuning, and monitoring. This book is designed to take you through the best practices of performing the real daily tasks of a Teradata DBA, and will help you tackle any problem you might encounter in the process.
Table of Contents (19 chapters)
Title Page
Dedication
Packt Upsell
Contributors
Preface
Index

Improving Teradata joins


In this recipe, we will list steps which will guide you to an overall health check of Teradata joins. This will be a high-level view of performance when it comes to JOINS. Steps in this recipe will not be dependent on type of join. You can apply these to any join, based on the problem in the query:

Getting ready

You need to connect to the Teradata database using SQLA or Studio.

How to do it...

  1. Connect to the Teradata database using SQLA or Studio.
  2. Write SHOW in front of the query and execute it to get the list of all objects in the query, with their definitions.
  3. Once you have the DDLs of all the objects, check the columns involved in joins.
  4. Execute EXPLAIN for the query by pressing F6 in SQLA or writing EXPLAIN in front of the query and pressing F5
  5. In EXPLAIN, check for extremely high estimated rows or extremely low estimated rows and time; if these estimations are not in relation to table statistics, refresh the stats on the columns:
/*High Estimated Explain*/
1) We do...