TeraData Basics，

TeraData Basics

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1. Basic concept

1.1 Parallel Processing

AMP(Access Module Processor)

1.2 Linear Scalability

All Teradata tables are spread across ALL AMPs

3. Four Different Primary Indexes

3.1 UPI

CREATE TABLE Employee_Table
( Employee_No       INTEGER
 ,Last_Name         CHAR(20)
 ,Mgr_No            VARCHAR(12)
 ,Salary            Decimal(10,2)
) UNIQUE PRIMARY INDEX(Employee_No)

Teradata hashes UPI to distribute the date to all the AMPs evenly

3.2 NUPI

CREATE TABLE Employee_Intl
( Employee_No       INTEGER
 ,Dept_No           INTEGER
 ,Last_Name         CHAR(20)
 ,Salary            Decimal(10,2)
) PRIMARY INDEX(Dept_No)

Teradata distributes same NUPI into one AMPs, normally unevenly

3.3 Multi-Column Primary Index

Apply to both UPI & NUPI

CREATE TABLE Employee_Intl
( Employee_No       INTEGER
 ,Dept_No           INTEGER
 ,First_Name        CHAR(10)
 ,Last_Name         CHAR(20)
 ,Salary            Decimal(10,2)
) PRIMARY INDEX(First_Name,Last_Name)

Where write query, you need to combine the multi-column primary index, in order to get single AMP retrieving.

SELECT FROM Employee_Intl WHERE First_Name = '' AND Last_Name = '';

3.4 No Primary Index Tables

Random distribution, which is always even.

CREATE TABLE Employee_Intl
( Employee_No       INTEGER
 ,Dept_No           INTEGER
 ,First_Name        CHAR(10)
 ,Last_Name         CHAR(20)
 ,Salary            Decimal(10,2)
) PRIMARY INDEX(First_Name,Last_Name)

When execute the query, it will do a full table scan, usually for staging, which makes loading data faster.

Or use it for Columnar design

CREATE TABLE Employee_Columnar
( Employee_No       INTEGER
 ,Dept_No           INTEGER
 ,First_Name        CHAR(10)
 ,Last_Name         CHAR(20)
 ,Salary            Decimal(10,2)
) No Primary Index
Partition By Column

• must be a NoPI table
• COLUMN keyword

4. Nodes

4.1 SMP Node

AMPs and Parsing Engines live inside SMP (Symmetric Multi-Processing) Nodes

AMPs share nothing, each of them has its own disk, memory, CPU

4.2 MPP

Two SMP nodes connected become one MPP (Massive Parallel Processing) system

4.3 Teradata Cabinet

4.4 Inside a Node

PDE - Parallel Database Extensions, which controls the BYNET

PE - Parsing Engines

Vproc - Virtual Processes

4.5 Boardless BYNET and Physical BYNET

Each PE controls every AMP, but why multiple PEs instead of one? Because each PE handles 120 sessions (users), which makes Teradata available for many users at the same time.

5. Hashing the primary index