15. The one or more non-transitory storage media of claim 14 , wherein the one or more factors specified by the query plan formation data indicates that a particular query rewrite optimization failed to eliminate said one or more operators associated with said one or more factors.
15. The one or more non-transitory storage media of claim 14 , wherein the one or more factors specified by the query plan formation data indicates that a particular query rewrite optimization failed to eliminate said one or more operators associated with said one or more factors. 16. The one or more non-transitory storage media of claim 15 , wherein the one or more factors specified by the query plan formation data further includes a reason why the particular query rewrite optimization failed to eliminate an operator of said one or more operators.