Teradata Basics for Business Users

Tom Coffing, Leona Coffing

• Publisher: Coffing Publishing
• Year: 2013
• eBook ISBN: 9781940540122
• Topic: Computer Science
• Subtopic: Data Warehousing
• Index: Computer Science

The brilliance behind the Tera-Tom Genius series is that each book gets deeper and deeper into the details of Teradata. The Business Users book begins with brilliant fundamentals before diving into how Teradata works, how data is laid out, how people are set up as users, and how they are tracked. Business Users will completely understand Teradata at the exact level they need to after reading this book.

Chapter 1 – The Teradata Fundamentals

“The man who doesn't read good books has no advantage over the man who can't read them.”

-Mark Twain

What is Parallel Processing?

“After enlightenment, the laundry”

-Zen Proverb

Tera-Tom's Parallel Processing Wash and Dry

“After parallel processing the laundry, enlightenment!”

-Teradata Zen Proverb

Two guys were having fun on a Saturday night when one said, “I've got to go and do my laundry.” The other said, “What?!” The man explained that if he went to the laundry mat the next morning, he would be lucky to get one machine and be there all day. But, if he went on Saturday night, he could get all the machines. Then, he could do all his wash and dry in two hours. Now that's parallel processing mixed in with a little dry humor!

The Basics of a Single Computer

How are we doing on orders today?

How would I know? I'm just a disk. I need to transfer the block of data to the memory, and that is a slow process.

Data on disk does absolutely nothing. When data is requested, the computer moves the data one block at a time from disk into memory. Once the data is in memory, it is processed by the CPU at lightning speed. All computers work this way. The “Achilles Heel” of every computer is the slow process of moving data from disk to memory. That is all you need to know to be a computer expert!

Teradata Parallel Processes Data

Teradata has been the pioneer in parallel processing since 1988 when Wells Fargo bought the first Teradata system. In the picture above, you see that we have 16 orders with four orders placed on each disk. It appears to be four separate computers, but this is one system. Teradata systems work just like a basic computer as they still need to move data from disk into memory, but Teradata divides and conquers.

The Teradata Architecture

The Parsing Engine (PE) takes the User's SQL and builds a Plan for each AMP to follow to retrieve the data. Parallel Processing is all about each AMP doing an equal amount of the work. If they start at the same time and end the same time, they are performing true Parallel Processing. All communication is done over the BYNET.

Parallel Architecture

The rows of a Teradata table are spread across all the AMPs, so each AMP can then process an equal amount of the rows when a USER queries the table. Every table is spread across every AMP as evenly as possible.

All Teradata Tables are spread across ALL AMPS

Each table dreams of spreading their rows equally across the AMPs. Notice in the picture above, that we have three tables, and each table spreads their rows across all AMPs. If there were 500 tables in the system, then all 500 tables would be spread across the AMPs. Every AMP is responsible for a portion of the rows on every table.

Teradata Systems can Add AMPs for Linear Scalability

4-AMP Test System.

Order_Table has 16 rows.

8-AMP Production System – with the same 16 rows

Teradata systems often start small, but as more data is added or more power is needed, more AMPs are added. Above, you can see that our system at first had four AMPs. The Order_Table has 16 rows and each AMP is responsible for four Order_Table rows. Our second system has upgraded to eight AMPs. The Order_Table still has 16 rows, but now each AMP is responsible for one two Order_Table rows. Teradata systems will often continue to grow, and some systems have thousands of AMPs.

Teradata Parallel Processing

Each AMP holds a portion of the rows for every table in the system.

This is a great picture to put in your mind of how Teradata works. The most...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• About Tom Coffing
• About Leona Coffing
• Contents
• Chapter 1 - The Teradata Fundamentals
• Chapter 2 - The Teradata Users' Fastest Queries
• Chapter 3 - Space
• Chapter 4 - The User Environment
• Chapter 5 - Three Options for Teradata Table Design
• Chapter 6 - Secondary Indexes
• Chapter 7 - How Joins Work under the Covers
• Chapter 8 - Collect Statistics
• Chapter 9 - View Functions
• Chapter 10 - Macro Functions
• Chapter 11 - Explain
• Chapter 12 - Temporal Tables Create Functions
• Chapter 13 - Temporary Tables
• Chapter 14 - Top SQL Commands Cheat Sheet
• Back Cover