Monitoring Database ActivityChapter 12 Monitoring Server and Database Activity 405Database Cache Information TableThe Database Cache Information table provides the following caching information:Maximum entry cachesize (in bytes)Indicates the size of the entry cache maintained by the directory. This value ismanaged by the “Maximum Cache Size” attribute. See “Tuning DatabasePerformance,” on page 422 for information on changing this value using theServer Console.Current entry cachesize (in entries)Indicates the total number of directory entries currently present in the entrycache.Maximum entry cachesize (in entries)Indicates the maximum number of directory entries that can be maintained in theentry cache. This value is managed by the “Maximum Entries in Cache” attribute.See “Tuning Database Performance,” on page 422 for information on changingthis value using the Server Console.Table 12-6 Database Performance Monitoring - Database Cache InformationPerformance Metric Current TotalHits Indicates the number of times the database cache successfully supplied arequested page. A page is a buffer of the size 2K.Tries Indicates the number of times the database cache was asked for a page.Hit ratio Indicates the ratio of database cache hits to database cache tries. The closer thisvalue is to 100%, the better. Whenever a directory operation attempts to find aportion of the database that is not present in the database cache, the directoryhas to perform a disk access to obtain the appropriate database page. Thus, asthis ratio drops towards zero, the number of disk accesses increases anddirectory performance drops.To improve this ratio, you can increase the amount of data that the directorymaintains in the database cache by increasing the value of the “MaximumCache Size” attribute. See “Tuning Database Performance,” on page 422 forinformation on changing this value using the Server Console.Pages read in Indicates the number of pages read from disk into the database cache.Pages written out Indicates the number of pages written from the cache back to disk. A databasepage is written to disk whenever a read-write page has been modified andthen subsequently deleted from the cache. Pages are deleted from the databasecache when the cache is full and a directory operation requires a database pagethat is not currently stored in cache.Table 12-5 Database Performance Monitoring - Summary Information (Continued)Performance Metric Current Total
