42. The system of claim 39 , wherein the transform module identifies a portion of the left deep operator tree requiring transformation into a bushy tree structure for generating a semantically correct query execution plan.
42. The system of claim 39 , wherein the transform module identifies a portion of the left deep operator tree requiring transformation into a bushy tree structure for generating a semantically correct query execution plan. 43. The system of claim 42 , wherein the transform module transforms said portion of the left deep operator tree into a bushy tree shape.