Teradata Beginner's Guide - Architecture

8/13/2019 Teradata Beginner's Guide - Architecture

1/12

BEGINNERS GUIDE - ARCHITECTURE


2/12

Before beginning..

Node

A hardware assembly containing several tightly coupled central processing units

(CPUs).


3/12

Before beginning contd..

SMP Symmetric Multi Processing

An SMP Teradata Database has a single node that contains multiple CPUs sharing a

memory pool.

MPP Massively Parallel Processing

Multiple SMP nodes working together comprise a larger, MPP implementation of aTeradata Database. The nodes are connected using the BYNET, which allows

multiple virtual processors on multiple nodes to communicate with each other.


4/12

Before beginning contd..


5/12

LOGICALARCHITECTURE

PARSING ENGINE

BYNET

AMP AMP AMP AMP AMPAMP

DISK DISK DISK DISK DISK DISK

Contd..


6/12

COMPONENTS IN DETAIL

PARSING ENGINE

A Parsing Engine (PE) is a virtual processor (vproc). It is made up of the

following software components: Session Control, the Parser, the Optimizer,

and the Dispatcher.

PE contd..


7/12

PARSING ENGINE

Session Control

Logon and Logoff

Parser

Interprets SQL statements and check syntax. Consults data dictionary to ensure that all objects exist.

Also checks the access rights for users.

Optimizer

Develops least expensive plan which are converted to executable steps.

To maximize throughput and reduce resource contention, optimizer should know

system configuration, available units of parallelism & data demographics.

Teradata optimizer is robust and intelligent.

Parallel aware and cost-based using full look-ahead capability.

PE contd..


8/12

PARSING ENGINE

Dispatcher

Controls the sequence in which steps are executed and passes the steps to BYNET.

Composed of two tasks- execution control and response control.

Makes sure that all AMPs have finished a step before the next step is dispatched.

Depending on nature of SQL requests, a step will be sent to one AMP or all AMPs.

Execution control Receives the step definitions from Parser.

Transmits them to appropriate AMPs for processing.

Receives status report from AMPs as they process the requests.

Passes the results to response control one AMPs have completed the processing.

Response Control Returns the result to the user.


9/12

BYNET

Dual-redundant, fault tolerant, bidirectional interconnect network that enables:

Automatic load balancing of message traffic.

Automatic reconfiguration after fault detection.

Scalable bandwidth as nodes are added.

Depending on the nature of dispatch request, the communication between nodes

may be a:

Broadcast message is routed to all nodes in the system.

Point to point message is routed to specific nodes.

Features of BYNET

Fault-tolerant

Load balanced

Scalable

High Performance


10/12

ACCESS MODULE PROCESSOR

The Access Module Processor is the virtual processor that is responsible for

managing a portion of the database.Each AMP holds portion of a table.

A database manager subsystem resides on each AMP. This subsystem will:

Lock database s and tables.

Create, modify or delete definitions of tables.

Insert, delete or modify rows within table. Retrieve information from definitions and tables.

Returns the result set to Dispatcher.


11/12

DISK ARRAYS

Disk Array is a configuration of disk drives that

utilizes specialized controllers to distribute dataand parity across disks while providing fast access

and data integrity.

The disk array controllers are referred to as dual

redundant active array controllers, which means

that both controllers are actively used, in additionto serving as backup for each other.

Each AMP vproc must have access to an array

controller, which in turn accesses the physical

disks. AMP vprocs are associated with one or more

ranks (or mirrored pairs) of data. The total diskspace associated with an AMP is called a vdisk. A

vdisk may have up to three ranks.


12/12

TYPES OF PARALLELISM IN TERADATA

Multi-AMP

A suitable primary index spreads the rows uniformly across all AMPS and hence a

query that uses more than one AMP is called Multi-AMP.

Multi-Step

Am AMP can do 81 tasks in parallel. For example in a multiple join statement,

Teradata prepares all tables simultaneously for join.

Multi-Statement

Placing two or more SQL statements inside same transaction. In BTEQ, users cando this by placing a semi-colon at the beginning of the second SQL statement..

This improves system performance as they reduce processing overhead and they

are atomic.

Teradata Beginner's Guide - Architecture

Documents