Optimizing Performance With the UME Cache 

Use

Use this procedure to improve the performance of the SAP NetWeaver Application Server (AS) Java, by changing the configuration properties of the cache of the user management engine (UME). Improper settings can impact system performance or affect how current the user data is on the server node.

The UME cache uses the following methods to keep the cache current:

●      Default caching time

●      Initial cache size

●      Notification time

Default Caching Time

Configuring the caching time is a trade-off between performance and how current the data in the cache is. Increase the cache time to improve performance. The system does not need to load information in the cache as often. However, you run the risk that data in the cache is no longer up-to-date.

 

Donna Moore logs on to the system. She is assigned to the Warehouse group, which includes the Warehouse role. The UME enters this data in the cache. Rodney Washington, the user administrator, removes one of the permissions on the Warehouse role. In doing so, he triggers the UME cache to automatically update the Warehouse role object in the cache. However, Donna’s user object in the cache still includes the permission Rodney removed from the role. This remains the case until the cache expires her object.

If you set the caching time too low, the data is up-to-date, but the UME must continually reload data in the cache.

Initial Cache Size

When the initial cache size is too small, the cache removes objects too quickly from the cache, reducing performance. When the initial cache size is too large, it reserves the memory needed by other applications. As a rule of thumb, configure the initial cache size to the maximum number of concurrent users you expect divided by the number of server nodes in the cluster. The more groups, roles, and other attachments, such as employee photos you associate with a given user, the larger each object entry is. The size of the object entry increases the memory footprint of the cache.

Notification time

By setting the notification time to a higher value, you increase performance at the cost of inconsistency of the cache data between nodes. Set this value higher if expect a high volume of changes to objects.

You configure these methods with UME properties. You can only set these properties at the cluster level and they apply to each node in the cluster.

Prerequisites

This procedure requires you to restart the SAP NetWeaver Application Server (AS) Java, so you should plan for the required down time while the AS Java restarts.

Procedure

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       1.      Configure the required UME properties.

For more information about editing UMEproperties, see Editing UME Properties.

There are properties for user, account, group, role, ACL, and principal objects. Each can be set independently, except for the notification time:

○       Default caching time

§         ume.cache.group.default_caching_time

§         ume.cache.principal.default_caching_time

§         ume.cache.role.default_caching_time

§         ume.cache.user.default_caching_time

§         ume.cache.user_account.default_caching_time

○       Initial cache size

§         ume.cache.acl.initial_cache_size

§         ume.cache.acl.permissions.initial_cache_size

§         ume.cache.group.initial_cache_size

§         ume.cache.principal.initial_cache_size

§         ume.cache.role.initial_cache_size

§         ume.cache.user.initial_cache_size

§         ume.cache.user_account.initial_cache_size

○       Notification time

ume.cache.notification_time

       2.      Restart the AS Java.

More Information:

●      UME Cache  

●      Monitoring the Performance of the UME Cache  

●      Refreshing the User Caches of the AS Java