added TODO

arangod/Aql/Optimizer.cpp

@@ -108,6 +108,10 @@ int Optimizer::createPlans (ExecutionPlan* plan) {
           return res;
         }
       }
+
+      // TODO: abort early here if we found a good-enough plan
+      // a good-enough plan is probably every plan with costs below some
+      // defined threshold. this requires plan costs to be calculated here
     }
     _plans.steal(newPlans);
     leastDoneLevel = maxRuleLevel;