UME
Cache
When a user logs on to the SAP NetWeaver Application Server (AS) Java, the user management engine (UME) reads the user’s group and role assignments:
· Direct group assignments
● Direct role assignments
● Indirect group assignments
● Indirect role assignments
From this information, the UME creates a list of UME actions and determines the permissions assigned to the user. The UME stores this information in a cache on the node where the user is logged in.
Permissions of a User Stored in the User Cache
Another example of a use of the UME cache is when an administrator looks for all the members of a group, the UME records information about the group and its members in the UME cache on the server.
The UME refreshes this cache whenever you change group or role assignments. By default, the UME refreshes the cache automatically after the user has been logged in for about an hour.
The cache uses a number of configurable methods to keep the cache current:
● Initial cache size
By default the UME is configured to cache the information for up to 500 objects. In actual operation, the number of objects cached can exceed the configured value temporarily. When the number of objects in the cache exceeds the initial cache size, the cache marks selected objects as candidates for deletion. When the garbage collector runs, it evaluates the entries and removes objects until the cache is down to the required size.
● Caching time
The UME enters a time stamp for the objects it places in the cache. By default, the cache holds objects for an hour before marking them as candidates for deletion.
● Notification time
The cache on a specific server node notifies the caches on other server nodes about changes in cached objects. By default, the cache sends these notices without delay.
More Information:
●
Monitoring the
Performance of the UME Cache