Changing Database Parameters 
Database parameters define the fundamental properties of a database instance. 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).
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
Prerequisites
You are logged on to the database as the database system administrator or as a DBM operator with server authorization for changing database parameters.
More information: Glossary, Server Permission
Procedure
In the context menu of the database, choose Administration.
Open the Parameters tab page.
The general database parameters are displayed.
General 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:
SAP MaxDB:
50% of the available working memory
SAP liveCache technology:
25% of the available working memory
Changes only apply after a restart of the database
Concepts of the Database System, Working Memory Areas
InstanceType
INSTANCE_TYPE
Database type:
OLTP
SAP MaxDB database
LVC
SAP liveCache Technology
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
More information: Database Administration,
Double-click the database parameter you want to change.
Enter the required data.
Attribute
Description
Active Value
Active value
New value
New value
Durability
(Not available for all database parameters)
Permanent
The change is permanent.
Running
The change takes effect immediately.
If necessary, restart the database.
More information: Starting or Stopping Databases
More Information
Database Administration, Database Parameters