Github user hvanhovell commented on a diff in the pull request:
https://github.com/apache/spark/pull/10335#discussion_r47827840
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/basicOperators.scala ---
@@ -126,6 +127,69 @@ case class Sample(
}
}
+case class Range(
+ start: Long,
+ step: Long,
+ numSlices: Int,
+ numElements: BigInt,
+ output: Seq[Attribute])
+ extends LeafNode
+{
+ override def outputsUnsafeRows: Boolean = true
+
+ protected override def doExecute(): RDD[InternalRow] = {
+ sqlContext
+ .sparkContext
+ .parallelize(0 until numSlices, numSlices)
+ .mapPartitionsWithIndex((i, _) => {
+ val partitionStart = (i * numElements) / numSlices * step + start
+ val partitionEnd = (((i + 1) * numElements) / numSlices) * step +
start
+ def getSafeMargin(bi: BigInt): Long =
+ if (bi.isValidLong) {
+ bi.toLong
+ } else if (bi > 0) {
+ Long.MaxValue
+ } else {
+ Long.MinValue
+ }
+ val safePartitionStart = getSafeMargin(partitionStart)
+ val safePartitionEnd = getSafeMargin(partitionEnd)
+ val bufferHolder = new BufferHolder(LongType.defaultSize)
+ val unsafeRow = new UnsafeRow
+
+ new Iterator[InternalRow] {
+ private[this] var number: Long = safePartitionStart
+ private[this] var overflow: Boolean = false
+
+ override def hasNext =
+ if (!overflow) {
+ if (step > 0) {
+ number < safePartitionEnd
+ } else {
+ number > safePartitionEnd
+ }
+ } else false
+
+ override def next() = {
+ val ret = number
+ number += step
+ if (number < ret ^ step < 0) {
+ // we have Long.MaxValue + Long.MaxValue < Long.MaxValue
+ // and Long.MinValue + Long.MinValue > Long.MinValue, so iff
the step causes a step
+ // back, we are pretty sure that we have an overflow.
+ overflow = true
+ }
+
+ bufferHolder.reset()
+ unsafeRow.pointTo(bufferHolder.buffer, 1,
bufferHolder.totalSize())
--- End diff --
Why point to the same buffer after every iteration? We could do this during
the construction of the iterator. ```BufferHolder``` might be overkill here,
pointing to an array of 16 bytes should also do the trick.
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