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

Using help and show to resolve query issues


To observe statistics on a table, we use the help stats command. This gives an overview of stats collected on the table level:

/*Help statistics*/
HELP STATISTICS ON web_clicks;

Date Time            Unique Values   Column Names
‐‐‐‐‐‐‐‐             ‐‐‐‐‐‐‐‐         ‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐‐   
17/07/07 10:49:55       100              * (represent number of rows in table)
17/07/07 10:49:55       100               date
  • Date Time: Represents the date and time of stats collected. Helps to identify how old stats are.
  • Unique Values: Number of unique values for a column, or combination of columns, in case of multi-column stats.
  • Column Name: Name of the column on which stats are collected. The HELP STATISTICS command is enhanced to show the expression statistics. It shows the name given to the expression statistics instead of the actual expressions.

Following is  the most popular diagnostic command. It will give you suggestions on stats that need to be collected...