Performance Database 
Performance Database
Definition
Release 4.6A of the CCMS (Computing Center Management System)
alert monitor (Transaction RZ20) delivers the performance database. You can use this to analyze the current performance data and to compare it with the values that were reported over a specific time period.The performance database stores and displays performance data that was reported to the monitoring architecture. By default, basic data of all performance attributes is recorded in the performance database: hourly average value, hourly sum of value and hourly occurrence (reporting counts). Therefore, each attribute has 24-hour basic data for each day, which is stored in a database table.
You can aggregate the basic daily data over a specific period of time for each hourly slot (x days, weekly, monthly, quarterly and yearly) and use this data for analysis. There is an aggregation hierarchy:
The overall concept of the performance database is to store as much information as possible, but at the same time to retain as little data as possible. As the performance database is constantly growing, it is reorganized on a regular basis according to the aggregate hierarchy described above. Data is marked for deletion and held for a defined number of days. If the data has not been used within the defined days, it is deleted. If it has been used, the data remains in the performance database until the next time the database is reorganized.
See also:
Creating and Scheduling a Reorganization Schema Displaying Performance Data Assigning a Reorganization Schema to an Attribute Group Maintaining the Performance Database