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

Optimizing queries


In this recipe, we will show you the basic steps that you can follow to optimize or tune a query. Please be aware that a query can be tuned via multiple methods. This recipe will provide some fundamental steps that can be applied to any query to optimize it as per its identified issue.

A query can show the following issues:

  • A product join
  • A skewed join
  • High CPU/IO steps
  • Skewed PI
  • Other factors such as using function in joins, joining unmatched columns, and many more

Getting ready

You need to connect to the Teradata system via SQLA or Studio. Identify the query that needs to be optimized.

How to do it...

The following are the steps for optimizing the query:

  1. List the data objects involved in the query. Do a show on query. Using the SHOW command before the query will display all the objects (tables, views, procs, macros) involved in the query:
**To get all the object in a query**

SHOW
SELECT USERNAME , tbl.queryid , AcctStringDate , startTime , CAST( (EXTRACT ( HOUR FROM ( ( FirstRespTime...