
122 Automated Physical Database Design and Tuning
alternatives include recommending indexes for only a subset of the tables
in the database or indexes that satisfy certain constraint (e.g., with at
most a certain number of columns or a given size).
Database scaling. An interesting variant of the physical design problem
results from using scaling factors for database tables. Suppose that we
want to understand how the physical database design should change if
the data volume grows by 500%. In this case, we can scale the actual ta-
ble cardinalities appropriately by temporarily modifying the statistical
information used by the optimizer. Specifically,