keep global limit

Author: ulysses-you

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala

@@ -1458,13 +1458,11 @@ object PushPredicateThroughJoin extends Rule[LogicalPlan] with PredicateHelper {
  */
 object EliminateLimits extends Rule[LogicalPlan] {
   private def canEliminate(limitExpr: Expression, childMaxRow: Option[Long]): Boolean = {
-    limitExpr.foldable &&
-      childMaxRow.isDefined &&
-      childMaxRow.get <= limitExpr.eval().toString.toInt
+    limitExpr.foldable && childMaxRow.exists { _ <= limitExpr.eval().toString.toInt }
   }
 
   def apply(plan: LogicalPlan): LogicalPlan = plan transformDown {
-    case GlobalLimit(l, child) if canEliminate(l, child.maxRows) =>
+    case Limit(l, child) if canEliminate(l, child.maxRows) =>
       child
     case LocalLimit(l, child) if canEliminate(l, child.maxRows) =>
       child