As your business changes, you change the Essbase database outline to capture new product lines, provide information on new scenarios, reflect new time periods, and so on. Some changes to a database outline affect the data storage arrangement, forcing Essbase to restructure the database.
Because changes that require restructuring the database are time-consuming (unless you discard the data before restructuring), consider deciding on such changes based on how they affect performance. See:
For information about clearing data and thus avoiding some restructuring, see CLEARDATA and CLEARBLOCK in Technical Reference for Oracle Essbase.