[NSE-581] Improve GetArrayItem(Split()) performance

native-sql-engine/core/src/main/scala/com/intel/oap/expression/ColumnarExpressionConverter.scala

@@ -387,6 +387,26 @@ object ColumnarExpressionConverter extends Logging {
             r.scale,
             convertBoundRefToAttrRef = convertBoundRefToAttrRef),
           expr)
+      case getArrayItem: GetArrayItem =>
+        getArrayItem.child match {
+          case strSplit: StringSplit =>
+            ColumnarTernaryOperator.create(
+              replaceWithColumnarExpression(
+                strSplit.str,
+                attributeSeq,
+                convertBoundRefToAttrRef = convertBoundRefToAttrRef),
+              replaceWithColumnarExpression(
+                strSplit.regex,
+                convertBoundRefToAttrRef = convertBoundRefToAttrRef),
+              replaceWithColumnarExpression(
+                getArrayItem.ordinal,
+                convertBoundRefToAttrRef = convertBoundRefToAttrRef),
+              new StringSplit(strSplit.str, strSplit.regex, getArrayItem.ordinal))
+          case other =>
+            throw new UnsupportedOperationException(
+              s" --> ${other.getClass} | ${other} is not currently" +
+                s" supported as child of GetArrayItem.")
+        }
       case b: BinaryExpression =>
         logInfo(s"${expr.getClass} ${expr} is supported, no_cal is $check_if_no_calculation.")
         ColumnarBinaryExpression.create(
@@ -441,6 +461,15 @@ object ColumnarExpressionConverter extends Logging {
         return true
       case c: Concat =>
         c.children.map(containsSubquery).exists(_ == true)
+      case getArrayItem: GetArrayItem =>
+        getArrayItem.child match {
+          case strSplit: StringSplit =>
+            strSplit.children.map(containsSubquery).exists(_ == true)
+          case other =>
+            throw new UnsupportedOperationException(
+              s" --> ${other.getClass} | ${other} is not currently" +
+                s" supported as child of GetArrayItem.")
+        }
       case b: BinaryExpression =>
         containsSubquery(b.left) || containsSubquery(b.right)
       case s: String2TrimExpression =>

native-sql-engine/core/src/main/scala/com/intel/oap/expression/ColumnarTernaryOperator.scala

@@ -73,7 +73,7 @@ class ColumnarSubString(str: Expression, pos: Expression, len: Expression, origi
 }
 
 // StringSplit, not functionality ready, need array type support.
-class ColumnarStringSplit(child: Expression, regex: Expression,
+class ColumnarStringSplitPart(child: Expression, regex: Expression,
                           limit: Expression, original: Expression)
     extends StringSplit(child: Expression,
       regex: Expression, limit: Expression)
@@ -86,11 +86,12 @@ class ColumnarStringSplit(child: Expression, regex: Expression,
     val supportedTypes = List(
       StringType
     )
-    if (supportedTypes.indexOf(child.dataType) == -1) {
+    if (supportedTypes.indexOf(dataType) == -1) {
       throw new UnsupportedOperationException(
-        s"${child.dataType} is not supported in ColumnarStringSplit.")
+        s"${child} | ${child.dataType} is not supported in ColumnarStringSplitPart.")
     }
   }
+  override def dataType: DataType = StringType
 
   override def doColumnarCodeGen(args: java.lang.Object)
   : (TreeNode, ArrowType) = {
@@ -101,7 +102,7 @@ class ColumnarStringSplit(child: Expression, regex: Expression,
     val (limit_node, limitType): (TreeNode, ArrowType) =
       limit.asInstanceOf[ColumnarExpression].doColumnarCodeGen(args)
 
-    val resultType = new ArrowType.Bool()
+    val resultType = new ArrowType.Utf8()
     val funcNode =
       TreeBuilder.makeFunction(
         "split_part", Lists.newArrayList(child_node, regex_node,
@@ -271,8 +272,8 @@ object ColumnarTernaryOperator {
     case ss: Substring =>
       new ColumnarSubString(src, arg1, arg2, ss)
       // Currently not supported.
-//    case a: StringSplit =>
-//      new ColumnarStringSplit(str, a.regex, a.limit, a)
+   case ssp: StringSplit =>
+     new ColumnarStringSplitPart(src, arg1, arg2, ssp)
     case st: StringTranslate =>
       new ColumnarStringTranslate(src, arg1, arg2, st)
     case sl: StringLocate =>