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Database parameters define fundamental properties of the database. They are divided into several groups. The following groups are relevant for users:

The database system stores the values of the database parameters in binary format in the PARAM database parameter file of the database.

Caution Caution

Do not change database parameter values directly in this file. Always use the procedures described below.

End of the caution.

The Database Messages log file also contains the current values of the database parameters (at the beginning of the log file). More information: Log Files

Changing Database Parameters

You can change the values of most database parameters.

Most changes to database parameters take effect only after the database has been restarted.

However, you can change certain database parameters while the database is running, that is in the ONLINE or ADMIN operational state (see the description of individual database parameters for more information). For these changes you can define when they are to become effective:

  • Until the next restart

  • After the next restart

  • Immediately and permanently

Use one of the following database tools:

Database Studio, Database Manager CLI, or CCMS (in SAP systems only)

More information:

You can also use these tools to display the history of the values of the database parameters.

Default Values, Value Ranges, and Calculation Formulas

The default parameter file cserv.pcf contains the default values, value ranges, calculation formulas, and properties of the database parameters.

More information:

When creating a new database, you have the following options:

  • Use the system default values for the database parameter

  • Use a copy of the database parameter file from another database

  • Import the database parameter file from a complete data backup.

If you change a database parameter whose value is normally calculated by the system, then the system takes this user-defined value for all subsequent recalculations of database parameter values. The system discards and recalculates this user-defined value only if it is not within the permitted value range (such a situation might occur, for example, after the database software has been updated).

Obsolete Database Parameters

Note Note

Starting with version 7.7.03 of the database software, the names of many database parameters have changed.

Some database parameters have also been designated obsolete. These parameters have either been removed already or will be removed in one of the next database versions.

More information: Obsolete Database Parameters

End of the note.

More Information

SAP Note 1139904 (FAQ MaxDB/liveCache Kernel Parameter)

Checking the Database Configuration