Webtrends Analytics 9 Adminstration Guide, November 2012
Analysis and report tables are cleared after all the periods for report analysis (such as daily, weekly, or monthly) are closed out, at which point the data resides only in the report database. (Report periods are defined on the Reports dialog of the profile settings.)
For example, say a profile only uses weekly periods. When all the daily data is collected for a week, the weekly table can be closed out and cleared because all the data it contained is now stored in the report database, which is also known as the On Demand Database (ODDB). Regardless of what periods you select, all analysis and report tables are closed out and cleared at the end of the year.
The data in the On Demand Database is stored indefinitely unless you enable the Report Data Retention job. This job trims report databases using the settings specified in the Report Retention dialog. To access the Report Database dialog, pane, click Disable this job? check box on the General dialog. The report database is trimmed when the job runs each day.. To enable the Report Data Retention job, click , edit the Report Data Retention job, and clear the