Fixed the number of tasks when the data of LocalRelation is empty.

Added optimization rule related to bool expression.

Author: sarutak

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

@@ -299,6 +299,18 @@ object BooleanSimplification extends Rule[LogicalPlan] {
           case (_, _) => or
         }
 
+      case not @ Not(exp) =>
+        exp match {
+          case Literal(true, BooleanType) => Literal(false)
+          case Literal(false, BooleanType) => Literal(true)
+          case GreaterThan(l, r) => LessThanOrEqual(l, r)
+          case GreaterThanOrEqual(l, r) => LessThan(l, r)
+          case LessThan(l, r) => GreaterThanOrEqual(l, r)
+          case LessThanOrEqual(l, r) => GreaterThan(l, r)
+          case Not(e) => e
+          case _ => not
+        }
+
       // Turn "if (true) a else b" into "a", and if (false) a else b" into "b".
       case e @ If(Literal(v, _), trueValue, falseValue) => if (v == true) trueValue else falseValue
     }

sql/core/src/main/scala/org/apache/spark/sql/execution/SparkStrategies.scala

@@ -274,9 +274,10 @@ private[sql] abstract class SparkStrategies extends QueryPlanner[SparkPlan] {
         execution.Sample(fraction, withReplacement, seed, planLater(child)) :: Nil
       case SparkLogicalPlan(alreadyPlanned) => alreadyPlanned :: Nil
       case logical.LocalRelation(output, data) =>
+        val nPartitions = if (data.isEmpty) 1 else numPartitions
         PhysicalRDD(
           output,
-          RDDConversions.productToRowRdd(sparkContext.parallelize(data, numPartitions))) :: Nil
+          RDDConversions.productToRowRdd(sparkContext.parallelize(data, nPartitions))) :: Nil
       case logical.Limit(IntegerLiteral(limit), child) =>
         execution.Limit(limit, planLater(child)) :: Nil
       case Unions(unionChildren) =>