diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala index 4abda21ffec96889325a1432c44646878b3f22a5..47bff0c730b8a2bf197d0870c3df1b3a9a79e49a 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala @@ -20,10 +20,10 @@ package org.apache.spark.sql.execution import scala.collection.mutable.ArrayBuffer import scala.reflect.runtime.universe.TypeTag +import org.apache.spark.{SparkEnv, HashPartitioner, SparkConf} import org.apache.spark.annotation.DeveloperApi -import org.apache.spark.{HashPartitioner, SparkConf} import org.apache.spark.rdd.{RDD, ShuffledRDD} -import org.apache.spark.sql.SQLContext +import org.apache.spark.shuffle.sort.SortShuffleManager import org.apache.spark.sql.catalyst.ScalaReflection import org.apache.spark.sql.catalyst.errors._ import org.apache.spark.sql.catalyst.expressions._ @@ -96,6 +96,9 @@ case class Limit(limit: Int, child: SparkPlan) // TODO: Implement a partition local limit, and use a strategy to generate the proper limit plan: // partition local limit -> exchange into one partition -> partition local limit again + /** We must copy rows when sort based shuffle is on */ + private def sortBasedShuffleOn = SparkEnv.get.shuffleManager.isInstanceOf[SortShuffleManager] + override def output = child.output /** @@ -143,9 +146,15 @@ case class Limit(limit: Int, child: SparkPlan) } override def execute() = { - val rdd = child.execute().mapPartitions { iter => - val mutablePair = new MutablePair[Boolean, Row]() - iter.take(limit).map(row => mutablePair.update(false, row)) + val rdd: RDD[_ <: Product2[Boolean, Row]] = if (sortBasedShuffleOn) { + child.execute().mapPartitions { iter => + iter.take(limit).map(row => (false, row.copy())) + } + } else { + child.execute().mapPartitions { iter => + val mutablePair = new MutablePair[Boolean, Row]() + iter.take(limit).map(row => mutablePair.update(false, row)) + } } val part = new HashPartitioner(1) val shuffled = new ShuffledRDD[Boolean, Row, Row](rdd, part)