The data collected by the database manager includes several accumulating counters. These counters are incremented during the operation of the database, for example, every time an application commits a transaction.
Counters are initialized when their applicable object becomes active. For example, the number of buffer pool pages read for a database (a basic element) is set to zero when the database is activated.
Counters under switch control are reset to zero when their associated switch is turned on.
Counters returned by event monitors are reset to zero when the event monitor is activated.