2. The system of claim 1 , wherein the clustering module is further configured: to identify a plurality of candidate merger inputs, each candidate merger input comprising an input query or an existing query cluster resulting from a previous pair-wise merging, a merger input graph pattern and a set of predicate edges contained in the merger input graph pattern; and to select a pair of merger inputs from the plurality of candidate merger inputs having a maximum overlap in the sets of predicate edges associated with the selected pair of merger inputs.
3. The system of claim 2 , wherein the clustering module comprises a Jaccard similarity comparison module to select the pair of merger inputs having a highest Jaccard similarity between the associated sets of predicate edges.