Github user mgaido91 commented on a diff in the pull request:
https://github.com/apache/spark/pull/21028#discussion_r187994904
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/collectionOperations.scala
---
@@ -529,6 +567,239 @@ case class ArrayContains(left: Expression, right:
Expression)
override def prettyName: String = "array_contains"
}
+/**
+ * Checks if the two arrays contain at least one common element.
+ */
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = "_FUNC_(a1, a2) - Returns true if a1 contains at least a
non-null element present also in a2. If the arrays have no common element and
they are both non-empty and either of them contains a null element null is
returned, false otherwise.",
+ examples = """
+ Examples:
+ > SELECT _FUNC_(array(1, 2, 3), array(3, 4, 5));
+ true
+ """, since = "2.4.0")
+// scalastyle:off line.size.limit
+case class ArraysOverlap(left: Expression, right: Expression)
+ extends BinaryArrayExpressionWithImplicitCast {
+
+ override def checkInputDataTypes(): TypeCheckResult =
super.checkInputDataTypes() match {
+ case TypeCheckResult.TypeCheckSuccess =>
+ if (RowOrdering.isOrderable(elementType)) {
+ TypeCheckResult.TypeCheckSuccess
+ } else {
+ TypeCheckResult.TypeCheckFailure(s"${elementType.simpleString}
cannot be used in comparison.")
+ }
+ case failure => failure
+ }
+
+ @transient private lazy val ordering: Ordering[Any] =
+ TypeUtils.getInterpretedOrdering(elementType)
+
+ @transient private lazy val elementTypeSupportEquals = elementType match
{
+ case BinaryType => false
+ case _: AtomicType => true
+ case _ => false
+ }
+
+ @transient private lazy val doEvaluation = if (elementTypeSupportEquals)
{
+ fastEval _
+ } else {
+ bruteForceEval _
+ }
+
+ override def dataType: DataType = BooleanType
+
+ override def nullable: Boolean = {
+ left.nullable || right.nullable ||
left.dataType.asInstanceOf[ArrayType].containsNull ||
+ right.dataType.asInstanceOf[ArrayType].containsNull
+ }
+
+ override def nullSafeEval(a1: Any, a2: Any): Any = {
+ doEvaluation(a1.asInstanceOf[ArrayData], a2.asInstanceOf[ArrayData])
+ }
+
+ /**
+ * A fast implementation which puts all the elements from the smaller
array in a set
+ * and then performs a lookup on it for each element of the bigger one.
+ * This eval mode works only for data types which implements properly
the equals method.
+ */
+ private def fastEval(arr1: ArrayData, arr2: ArrayData): Any = {
+ var hasNull = false
+ val (bigger, smaller) = if (arr1.numElements() > arr2.numElements()) {
+ (arr1, arr2)
+ } else {
+ (arr2, arr1)
+ }
+ if (smaller.numElements() > 0) {
+ val smallestSet = new mutable.HashSet[Any]
+ smaller.foreach(elementType, (_, v) =>
+ if (v == null) {
+ hasNull = true
+ } else {
+ smallestSet += v
+ })
+ bigger.foreach(elementType, (_, v1) =>
+ if (v1 == null) {
+ hasNull = true
+ } else if (smallestSet.contains(v1)) {
+ return true
+ }
+ )
+ }
+ if (hasNull) {
+ null
+ } else {
+ false
+ }
+ }
+
+ /**
+ * A slower evaluation which performs a nested loop and supports all the
data types.
+ */
+ private def bruteForceEval(arr1: ArrayData, arr2: ArrayData): Any = {
+ var hasNull = false
+ if (arr1.numElements() > 0) {
+ arr1.foreach(elementType, (_, v1) =>
+ if (v1 == null) {
+ hasNull = true
+ } else {
+ arr2.foreach(elementType, (_, v2) =>
+ if (v1 == null) {
+ hasNull = true
+ } else if (ordering.equiv(v1, v2)) {
+ return true
+ }
+ )
+ })
+ }
+ if (hasNull) {
+ null
+ } else {
+ false
+ }
+ }
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ nullSafeCodeGen(ctx, ev, (a1, a2) => {
+ val smaller = ctx.freshName("smallerArray")
+ val bigger = ctx.freshName("biggerArray")
+ val comparisonCode = if (elementTypeSupportEquals) {
+ fastCodegen(ctx, ev, smaller, bigger)
+ } else {
+ bruteForceCodegen(ctx, ev, smaller, bigger)
+ }
+ s"""
+ |ArrayData $smaller;
+ |ArrayData $bigger;
+ |if ($a1.numElements() > $a2.numElements()) {
+ | $bigger = $a1;
+ | $smaller = $a2;
+ |} else {
+ | $smaller = $a1;
+ | $bigger = $a2;
+ |}
+ |if ($smaller.numElements() > 0) {
+ | $comparisonCode
+ |}
--- End diff --
Yes, but anyway is it initiated to `false`, unless one of the input is
`null`. And in that case we don't even reach this point because we just return
`null`.
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