Top DB Files
The Top DB Files subsection lists the database files that accounted for the highest percentages of sampled session activity. Only cluster and I/O events are considered. The % Event column breaks down the activity by event, so if multiple rows exist in this table, then the sampled activity is divided among multiple events.
Figure 8-7 shows that about 11 percent of DB time involves waits for the UNDOTBS tablespace. This information is consistent with Figure 8-4, which shows significant DML activity from multiple sessions.
