General Database Parameters 
The following overview describes database parameters belonging to the General Database Parameters group.
For information about other database parameters, see
To change the values of database parameters, 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
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).
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
Name (from version 7.7.03) |
Old Name (up to and including version 7.7.02) |
Description |
Change Restrictions |
More Information |
|---|---|---|---|---|
AutoLogBackupSize |
LOG_SEGMENT_SIZE |
Log segment size (in pages) When automatic log backup is activated and no time interval has been configured, then the database system makes an automatic log backup as soon as a log segment is full. 0: system uses 1/3 of the log area as the log segment size ≤50% of the log area: system uses the value defined in AutoLogBackupSize > 50% of the log area: system uses 50% of the log area as the log segment size |
Changes only apply after a restart of the database |
Database Administration, Backing Up Log Entries |
CacheMemorySize |
CACHE_SIZE |
Size of the I/O buffer cache = data cache + converter (in pages) If no value has been specified, the system calculates the value of this parameter as follows:
|
Changes only apply after a restart of the database |
Concepts of the Database System, Working Memory Areas |
InstanceType |
INSTANCE_TYPE |
Database type:
You define the database type when you create the database. |
Cannot be changed |
Concepts of the Database Systems, |
KernelVersion |
KERNELVERSION |
Version of the database software When you install a new version of the database software, the database system updates the value of this parameter. |
Users cannot change this value |
|
MaxBackupMedia |
MAXBACKUPDEVS |
Maximum number of files or tape devices for parallel backup |
Changes only apply after a restart of the database |
Database Administration, Backup Templates and Data Carriers |
MaxCPUs |
MAXCPU |
Maximum number of processors to which the database system can distribute user tasks. When choosing this value, bear in mind that your computer's operating system resources have to be available for other programs as well. |
Changes only apply after a restart of the database |
SAP Note 936058 |
MaxDataVolumes |
MAXDATAVOLUMES |
Maximum number of data volumes |
Changes only apply after a restart of the database |
Concepts of the Database System, Volumes (Permanent Storage) |
MaxLogVolumes |
MAXLOGVOLUMES |
Maximum number of log volumes |
Changes only apply after a restart of the database |
|
MaxSQLLocks |
MAXLOCKS |
Maximum number of locks |
Changes only apply after a restart of the database |
Concepts of the Database System, Locks |
MaxUserTasks |
MAXUSERTASKS |
Maximum number of simultaneously active user tasks and therefore the maximum number of database sessions If this number has been reached, then no additional user can log on to this database. If you choose a very high value for MaxUserTasks, the database system requires a lot of address space, particularly for local communication via shared memory. For SAP systems (OLTP), we recommend the following minimum value: 2 x <number_of_SAP_processes> + 4 |
Changes only apply after a restart of the database |
Concepts of the Database System, Tasks SAP Note 757914 |
MCODIndicator |
MCOD |
MCOD = Multiple Components One Database In SAP systems, indicates if other applications use the database |
Changes only apply after a restart of the database |
|
RunDirectoryPath |
RUNDIRECTORY |
Run directory of the database A relative path is interpreted relatively to the independent data path. |
Changes only apply after a restart of the database |
Glossary, Run Directory |
UseMirroredLog |
LOG_MIRRORED |
Specifies whether the database system mirrors the log area This parameter is relevant only when you create a mirror volume with the Database Manager CLI. Database Studio automatically adjusts this parameter when a mirror volume is created. |
Changes only apply after a restart of the database |
Glossary, Log Mode |