Data collection periods
Most DB2 windows mode statistics are available as interval and session counts, except for current thread information, which is measured for the life of the thread to the time of the query.
Interval data represents the near-term performance of your DB2 targets. Typically, the interval is defined as 15 minutes. When you issue a view query for interval data, MainView for DB2 displays data for the current interval, which means that you see data from the beginning of this interval until the query was issued. The data collected represents that portion of the interval that has elapsed, some time between 1 to 15 minutes. This result is similar to the DELTA concept in the MainView for DB2 full-screen displays.
Session data represents a summary of performance information since the monitored DB2 system started.
Naming conventions for the views differentiate between these types of data. If the data shown is interval data, the view name contains no special suffix, while session data views are suffixed with an S. For example, total I/O counts per page set are shown for the interval in view PSTIO, while session counts are shown in PSTIOS.
Many detail DB2 statistics views show both interval and session counts together.
The monitor data available in windows mode is more granular, and includes real-time values for the most recent period, typically the last 60 to 90 seconds. This data provides a much better indication of current problems. Real-time views are suffixed with an R.
Some monitor views contain all three periods in one view. These cluster views provide a better perspective of how these indicators have behaved over time. Cluster views are suffixed with a C.
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