20 Performance Tuning for Content Manager
2.1 DB2 Universal Database overview
Library Server uses a relational database, and Resource Manager also uses a
relational database. IBM DB2 Universal Database (DB2) is a multimedia,
Web-ready, relational database management system (RDBMS). It is available on
z/OS, UNIX®, Windows, and AS/400® platforms. Understanding DB2 is critical
to achieving success in performance tuning for Content Manager systems.
There are many well-written publications on DB2 that contain very useful
information. Most of the material presented in the following sections is extracted
from these publications:
IBM DB2 Universal Database Version 8.2 Administration Guide: Planning,
SC09-4822
IBM DB2 Universal Database Version 8.2 Administration Guide: Performance,
SC09-4821
IBM DB2 UDB V8 and WebSphere V5 Performance Tuning and Operation
Guide, SG24-7068
We include what we think is important to give you a quick start in the basic
concepts of DB2, as well as aspects of performance tuning for the DB2 database
system and routine maintenance that should be performed. For a more in-depth
understanding of DB2, we recommend that you read these publications because
they proved to be extremely helpful for us.
2.1.1 Basic DB2 database concepts
In this section, we introduce some of the basic relational database concepts. This
includes an overview of the various database objects and the database
configuration files.
Database objects
Database objects are the components that make up a DB2 relational database.
Some of the more important database objects are: instances, databases,
database partition groups, tables, views, indexes, schemas, system catalog
tables, buffer pools, table spaces, containers, and stored procedures.
Figure 2-1 on page 21 displays the database objects relationship. The individual
components of the database objects will be discussed throughout this section.
Chapter 2. Content Manager base products 21
Figure 2-1 Database objects relationship
Instances (database managers)
An instance (also known as a database manager) is DB2 code that manages
data. It controls what can be done to the data, and manages system resources
that are assigned to it. Each instance is a complete environment. If the database
system is parallel, it contains all of the database partitions. An instance has its
own databases (which other instances cannot access), and all its database
partitions share the same system directories. It also has separate security from
other instances on the same machine or system.
Databases
A relational database presents data as a collection of tables. A table consists of a
defined number of columns and any number of rows. Each database includes a
set of system catalog tables that describe the logical and physical structure of the
data, a configuration file containing the parameter values allocated for the
database, and a recovery log with ongoing transactions and transactions to be
archived.
System
Database
Database partition group
Table spaces
Tables
Indexes
Long data
Instance

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