6. The method of claim 2 , further comprising computing the data profile through a result set profiler module through which: a first set of hash tables maps each attribute value of an attribute to a number of times a particular value is observed in the attribute, and a second set of hash tables maps patterns exhibited by an attribute value to a count of a number of times a pattern is observed in the attribute, wherein the pattern is constructed based on a regular expression of string-valued attributes.
2. The method of claim 1 , wherein the set of characteristics includes metadata of the initial query comprising at least one of: a number of attributes in the initial result set, a data type of each of the attributes, a frequency of usage per user, a uniqueness constraint on the attributes, anullability of individual attributes, and a functional dependency between the attributes.