Delta records

The delta record is an OMEGAMON for Db2 Performance Expert term for a set of counters that describes the activity of a Db2 system between two consecutive DB2 Statistics record pairs.

For example, if a DB2 Statistics record pair is externalized at time t1 and the next DB2 Statistics record pair is externalized at t2, OMEGAMON for Db2 Performance Expert creates only one delta record, which represents the Db2 system activity between t1 and t2.

A counter in the delta record, like the counters in the DB2 Statistics record pairs, is provided in one of the following forms:

• Accumulated value. For example, the total number of SELECT statements that are executed between two consecutive DB2 Statistics record pairs. The accumulated value from a delta record is generally smaller than the accumulated value from the DB2 Statistics record pair which marks the end of the delta record and provides the values accumulated since the Db2 system was last started.
• Current or snapshot value. For example, the number of open data sets at the end of the delta record. It is the same as the value provided in the DB2 Statistics record pair which marks the end of the delta record.
• The maximum or high-water mark value the counter reached from the time the system was last started until the end of the delta record, for example, the maximum number of open data sets. It is the same as the value provided in the DB2 Statistics record pair which marks the end of the delta record.

When a delta record is calculated, OMEGAMON for DB2 PE externalizes it to Statistics traces and File data sets depending on your specification.