Database parameters define fundamental properties of the database.
When creating a new database, you can use the system default for the database parameter values, copy the database parameter file from a different database, or else import the database parameter file from a complete data backup.
Database parameters are divided into the following groups:
liveCache Database Parameters (for SAP liveCache databases only)
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
The database system saves the values of the database parameters in binary format in the PARAM database parameter file of the database.
Caution
Do not change database parameter values directly in this file, but as described below.
The default parameter file cserv.pcf contains the default values, value ranges, calculation formulas and properties of the database parameters.
More information:
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 individual 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
If you change a database parameter whose value is normally calculated by the system, then the system will consider 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 (for example, after the database software has been updated).
Use one of the following database tools:
Database Studio, Database Manager CLI, or CCMS (in SAP systems only)
More information:
Database Studio, Changing Database Parameters
Database Manager CLI Tutorial, Changing the Values of Database Parameters
Database Administration in CCMS, Parameters
You can also use these tools to display the history of the values of the database parameters.
SAP Note 1139904 (FAQ MaxDB/liveCache Kernel Parameter)