9. A method for rewriting a query during a database query processing operation, comprising the steps of: processing the query having one or more one or more target attributes in accordance with at least a portion of a data set producing query results comprising the one or more target attributes and one or more auxiliary attributes, wherein the one or more auxiliary attributes are not included in the query; comparing the query results to at least the portion of the data set to determine a relative selectivity for the one or more auxiliary attributes; and appending the query with at least one new predicate corresponding to at least one of the one or more auxiliary attributes having a high relative selectivity to form a rewritten query; wherein the step of appending the query with at least one new predicate comprises: selecting at least one of the one or more auxiliary attributes based at least in part on a ranking of the determined relative selectivity for the one or more auxiliary attributes; and appending the query with at least one new predicate corresponding to the selected at least one of the one or more auxiliary attributes to form the rewritten query.
9. A method for rewriting a query during a database query processing operation, comprising the steps of: processing the query having one or more one or more target attributes in accordance with at least a portion of a data set producing query results comprising the one or more target attributes and one or more auxiliary attributes, wherein the one or more auxiliary attributes are not included in the query; comparing the query results to at least the portion of the data set to determine a relative selectivity for the one or more auxiliary attributes; and appending the query with at least one new predicate corresponding to at least one of the one or more auxiliary attributes having a high relative selectivity to form a rewritten query; wherein the step of appending the query with at least one new predicate comprises: selecting at least one of the one or more auxiliary attributes based at least in part on a ranking of the determined relative selectivity for the one or more auxiliary attributes; and appending the query with at least one new predicate corresponding to the selected at least one of the one or more auxiliary attributes to form the rewritten query. 16. The method of claim 9 , further comprising the step of performing a query processing operation on the data set with a rewritten query.