20. The apparatus of claim 19 , further comprising one or more computer programs for determining a subpredicate combined selectivity estimate of the unapplied eligible predicates using column distribution statistics of the pre-defined query.
20. The apparatus of claim 19 , further comprising one or more computer programs for determining a subpredicate combined selectivity estimate of the unapplied eligible predicates using column distribution statistics of the pre-defined query. 21. The apparatus of claim 20 , wherein a cardinality ratio comprises a ratio of a cardinality of the pre-defined query to a product of cardinalities of base tables referenced in the pre-defined query and the query.