You can view details on usage of repository caches with the Administrative Interface Component Browser. For example, the Profile Repository’s page in the Component Browser can be found at:

http://hostname:port/dyn/admin/nucleus/atg/userprofiling/ProfileAdapterRepository/

where hostname is the name of the application server’s host machine, and port is the port where the application server listens for HTTP requests. Cache metrics are displayed under the heading Cache Usage Statistics.

You should monitor cache usage during testing and after deployment, in order to determine the cache sizes required to optimize application performance. For example, if the item cache records a high number of failed access tries and no successful tries, it is likely that caching items of this type yields no benefit and caching can be disabled; if it shows a mix of successful and unsuccessful access tries, the cache is probably too small; and if it records a high number of successful access tries and no failures, the cache is probably big enough.

The cache usage statistics table contains the following data:

Property

Description

entryCount

Current number of cache entries

cacheSize

Maximum cache size

usedRatio

Percent of the cache in use. If the value is close to 100, you should probably increase the item descriptor’s cacheSize setting.

accessCount

Total tries, successful and unsuccessful, to retrieve items or query results since cache startup

hitCount

Total number of successful access tries since cache startup

missCount

Total number of failed access tries since cache startup

hitRatio

The hitCount percentage of accessCount. For example, if accessCount is 100 and hitCount is 75, hitRatio is 75%.

cacheInvalidations

Number of times the entire cache was invalidated since cache startup

entryInvalidations

Number of invalidated entries since cache startup

You can also examine the contents of a cache in the Admin UI, by executing the XML tag <dump-caches<dump-caches> on a repository. See Preloading Caches later in this chapter.