9. The method of claim 2 , further comprising: inputting an OP node of arity K; inputting sets of matches for each child of the OP node; selecting a match from a match set; and testing the selected match set to determine whether the selected match is a full-candidate match.
2. The method of claim 1 , further comprising deriving the candidate matches for subplans of a given execution plan using the power hints query language expression and the direct acyclic graph.