For each XML entity cache, you can
      monitor a set of statistics that describes how the cache is being used
      and its effectiveness. These statistics describe:
      
        - The current state of the cache, such as how much memory and disk
        space is currently being used, the current number of entries in the
        cache, and so on.
- The cumulative activity for the current session, typically since
        the server started, such as the total number of entries that have
        lived in the cache, the total number of memory and disk page purges,
        and so on.
- The cumulative activity since the cache was created. The type of
        data is the same as the cumulative activity for a session, although
        the numbers reflect historical data since the cache was created.
To monitor an XML entity cache: