The following Pega 7 Platform database tables can store instances of Log- classes. For example, the pr_changelog table holds instances of the concrete classes derived from Log-System-. They record schema changes made using the Property Optimization tool and the Modify Schema tab.
The key to these instances contains a date and time in UTC format.
The Pega-RULES agent normally runs the standard Code-.SystemCleaner activity once each day for housekeeping tasks, including purging older records (instances) from certain log tables. In addition, the License Compliance facility includes built-in daily and end-of-period purging of Log- classes.