DB2 V8 Database Base (ii)

5 Configuration parameters

5.1 Configuration parameters

When you create a DB2 instance or database, the corresponding configuration file is created using the default parameter values. You can modify these parameter values to improve performance.

Configuration files contain specific parameters that define values such as resources assigned to DB2 products and individual databases, as well as diagnostic levels, with two types of profiles

Database Manager configuration file for each DB2 instance

Database configuration files for each independent database

The Database Manager configuration file is created when the DB2 instance is created. It contains parameters that affect system resources at the instance level and are unaffected by any database that is part of the instance. Depending on the configuration of your system, you can change the values of many of these parameters to a non system default value to improve performance or increase capacity.

There is also a Database manager configuration file for each client installation.

The database Manager configuration parameters are stored in a file named Db2systm. This file is created when you create an instance of the database manager. In Unix, in the Sqllib subdirectory of the instance of the Database manager, in Windows, the default location is the instance subdirectory of the Sqllib directory. If you set the DB2INSTPROF variable, the file is in the instance subdirectory specified by Db2instprof.

The database configuration file is created when the database is created and resides where the database resides. Each database has a configuration file. Its parameters specify the amount of resources to be assigned to the database, as well as other matters.

DB2 variables are divided into instance environment variables and database environment variables, the port of the instance typically defaults to 50000

5.2 Registry variables and environment variables

Environment variables and registry variables control the database environment.

Use the profile registry to allow centralized control of environment variables. Different levels of support are now available through different profiles. Remote administration of environment variables is also provided when using the DB2 Management Server.

There are four profiles in the registry:

DB2 The instance-level profile registry.

Most DB2 environment variables are located in this registry.

The environment variable settings for a particular instance are saved in this registry.

The values defined at this level will overwrite the corresponding settings at the global level.

DB2 Global-Level profile registry

This registry is used if the environment variable is not set on a specific instance.

This registry has settings for some environment variables within the current machine scope.

In DB2 UDB ese, there is a global level profile on each machine.

DB2 instance node level profile registry

In a partitioned environment, this registry basically contains variable settings for a specific partition (node).

This base-defined value overrides the corresponding settings for the instance-level and global-level.

DB2 Instance Profile Registry

This registry contains a list of all instance names that can be recognized by this system.

You can view the list by db2ilist.