Administration Guide

Database Manager Parameters

Database manager parameters are stored in a file named db2systm. This file is created when the instance of the database manager is created. In UNIX-based environments, this file can be found in the sqllib subdirectory for the instance of the database manager. In all other environments, the default location of this file is the instance subdirectory of the sqllib directory. If the DB2INSTPROF variable is set, the file is in the instance subdirectory of the directory specified by the DB2INSTPROF variable.

In a partitioned database environment, this file resides on a shared file system so that all database partition servers have access to the same file. The configuration of the database manager is the same on all database partition servers.

Most of the parameters either affect the amount of system resources that will be allocated to a single instance of the database manager, or they configure the setup of the database manager and the different communications subsystems based on environmental considerations. In addition, there are other parameters that serve informative purposes only and cannot be changed. All of these parameters have global applicability independent of any single database stored under that instance of the database manager.

The db2systm file cannot be directly edited. It can only be changed or viewed using a supplied API or by a tool which calls that API.

Attention: If you edit the file using a method other than those provided by the product, you may make your system unusable. We strongly recommend that you do not change this file using methods other than those documented and supported by DB2.

You may use one of the following methods to reset, update, and view the database managerconfiguration parameters:

• Using the DB2 Control Center. The DB2 Control Center provides the Configure Instance notebook, which you can use to set the database manager configuration parameters on either a client or a server. The DB2 Control Center also provides the Performance Configuration SmartGuide to alter the value of configuration parameters on a server. This SmartGuide generates values to parameters based on the responses you provide to a set of questions, such as the workload and the type of transactions that run against the database. See the online help available with the Control Center for information on using these interfaces.

• Using the command line processor. Commands to change the settings can be quickly and conveniently entered. See the Command Reference for more information about the following commands:

  • GET DATABASE MANAGER CONFIGURATION (or GET DBM CFG)

  • UPDATE DATABASE MANAGER CONFIGURATION (or UPDATE DBM CFG)

  • RESET DATABASE MANAGER CONFIGURATION (or RESET DBM CFG).

• Using the application programming interfaces (APIs). The APIs can easily be called from an application. See the Administrative API Reference for more information.

• Using the Client Configuration Assistant. You can only use the Client Configuration Assistant to set the database manager configuration parameters on a client.

After changing the parameters, the database manager must be stopped (db2stop) and then restarted (db2start) for the new parameter values to take effect. For clients, changes in the database manager configuration parameters take effect the next time the client connects to a server. While new parameter values are not immediately effective, viewing the parameter settings will always show the latest updates.

Note:

You do not need to restart the database manager if you update the value of the dft_monswitches parameter; this parameter is updated automatically when you change its value.

[ DB2 List of Books | Search the DB2 Books ]