## liveCache Database Parameters

### Use

The database system uses liveCache database parameters only for SAP liveCache database instances.

For more information about other database parameters, see General Database Parameters, Special Database Parameters and Support Database Parameters.

Changes to database parameters do not take effect until the database instance is restarted.

You can also change some database parameters while the database is running. In addition you can choose how long the change is to be effective for these database parameters:

■ Until the next restart

■ Not until after the next restart

■ Immediately and permanently

### Prerequisites

You use a SAP liveCache database instance.

### Features

SAP customers can find a detailed description of the liveCache database parameters in SAP note 833216.

liveCache Database Parameters

Parameter | Meaning | How can I change this Parameter?

MIN_RETENTION_TIME

MAX_RETENTION_TIME

Defines (in minutes) when the garbage collectors start deleting the history data (undo log entries and links to them)

The garbage collectors start deleting the history data in the following cases:

● When the data area is more than 90% full, the garbage collectors delete all history data that is older than MIN_RETENTION_TIME.

● When the data area is less than 90% full, the garbage collectors delete all history data that is older than MAX_RETENTION_TIME.

See History Management.

Can be changed during operation

OMS_HEAP_COUNT | Defines whether the OMS heap is divided into segments If the OMS heap is not subdivided, the internal heap memory management locks the entire OMS heap whenever a DB procedure requests or releases memory. | Changes only apply after restart
OMS_HEAP_LIMIT | Defines the maximum size of the OMS heap (in KB) | Changes only apply after restart
OMS_HEAP_THRESHOLD | Defines memory usage by the OMS heap (in %) | Changes only apply after restart
OMS_VERS_THRESHOLD | Defines memory usage by the OMS heap (in KB) | Changes only apply after restart

See also:

Database Administration in CCMS: SAP liveCache Technology, Configuring Parameters