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Manmohan Sharma, Lovely Professional University Unit 13: Parallel Databases

Unit 13: Parallel Databases Notes

CONTENTS
Objectives
Introduction
13.1 Parallel Database
13.2 I/O Parallelism
13.2.1 Horizontal Partitioning

13.2.2 Vertical Partitioning
13.3 Inter-query Parallelism
13.4 Intra-query Parallelism
13.5 Inter-operation and Intra-operation Parallelism
13.6 Summary
13.7 Keywords
13.8 Self Assessment

13.9 Review Questions
13.10 Further Readings

Objectives

After studying this unit, you will be able to:
 Describe parallel database

 Define I/O parallelism
 Explain inter- and intra-query parallelism
 Realise intra- and inter-operation parallelism

Introduction

In today’s world, Client-Server applications that rely on a database on the server as a data store
while servicing requests from multiple clients are quite commonplace. Most of these applications
use a Relational Database Management System (RDBMS) as their data store while using an
object oriented programming language for development. This causes a certain inefficiency as
objects must be mapped to tuples in the database and vice versa instead of the data being stored
in a way that is consistent with the programming model. The “impedance mismatch” caused by
having to map objects to tables and vice versa has long been accepted as a necessary performance
penalty.

13.1 Parallel Database

A parallel database system is one that seeks to improve performance through parallel
implementation of various operations such as loading data, building indexes, and evaluating
queries. Although data may be stored in a distributed fashion in such a system, the distribution
is governed solely by performance considerations.

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