If the source tables change significantly, you might want the Integration Service to create new aggregate data, instead of using historical data. To have the Integration Service create new aggregate data, configure the session to reinitialize the aggregate cache.
For example, you can reinitialize the aggregate cache if the source for a session changes incrementally every day and completely changes once a month. When you receive the new source data for the month, you might configure the session to reinitialize the aggregate cache, truncate the existing target, and use the new source table during the session.
After you run a session that reinitializes the aggregate cache, edit the session properties to disable the Reinitialize Aggregate Cache option. If you do not clear Reinitialize Aggregate Cache, the Integration Service overwrites the aggregate cache each time you run the session.
When you move from Windows to UNIX, you must reinitialize the cache. Therefore, you cannot change from a Latin1 code page to an MSLatin1 code page, even though these code pages are compatible.