Storage used by automatic statistics collection and reorganization
The automatic statistics collection and reorganization features store working data in tables that are part of your database. These tables are created in the SYSTOOLSPACE table space.
SYSTOOLSPACE is created automatically with default options when the database is activated. Storage requirements for these tables are proportional to the number of tables in the database and can be estimated at approximately 1 KB per table. If this is a significant size for your database, you might want to drop and then recreate the table space yourself, allocating storage appropriately. Although the automatic maintenance and health monitoring tables in the table space are automatically recreated, any history that was captured in those tables is lost when you drop the table space.