davidm-db commented on code in PR #48794:
URL: https://github.com/apache/spark/pull/48794#discussion_r1834234445
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sql/core/src/main/scala/org/apache/spark/sql/scripting/SqlScriptingExecutionNode.scala:
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@@ -649,3 +652,145 @@ class LoopStatementExec(
body.reset()
}
}
+
+/**
+ * Executable node for ForStatement.
+ * @param query Executable node for the query.
+ * @param variableName Name of variable used for accessing current row during
iteration.
+ * @param body Executable node for the body. If variableName is not None, will
have DropVariable
+ * as the last statement.
+ * @param label Label set to ForStatement by user or None otherwise.
+ * @param session Spark session that SQL script is executed within.
+ */
+class ForStatementExec(
+ query: SingleStatementExec,
+ variableName: Option[String],
+ body: CompoundBodyExec,
+ label: Option[String],
+ session: SparkSession) extends NonLeafStatementExec {
+
+ private object ForState extends Enumeration {
+ val VariableDeclaration, VariableAssignment, Body = Value
+ }
+ private var state = ForState.VariableDeclaration
+ private var currRow = 0
+ private var currVariable: Expression = null
+
+ private var queryResult: Array[Row] = null
+ private var isResultCacheValid = false
+ private def cachedQueryResult(): Array[Row] = {
+ if (!isResultCacheValid) {
+ query.isExecuted = true
+ queryResult = Dataset.ofRows(session, query.parsedPlan).collect()
+ isResultCacheValid = true
+ }
+ queryResult
+ }
+
+ /**
+ * Loop can be interrupted by LeaveStatementExec
+ */
+ private var interrupted: Boolean = false
+
+ private lazy val treeIterator: Iterator[CompoundStatementExec] =
+ new Iterator[CompoundStatementExec] {
+ override def hasNext: Boolean =
+ !interrupted && cachedQueryResult().length > 0 && currRow <
cachedQueryResult().length
+
+ override def next(): CompoundStatementExec = state match {
+ case ForState.VariableDeclaration =>
+ // when there is no for variable, skip var declaration and iterate
only the body
+ if (variableName.isEmpty) {
+ state = ForState.Body
+ body.reset()
+ return next()
+ }
+ currVariable =
createExpressionFromValue(cachedQueryResult()(currRow))
+ state = ForState.VariableAssignment
+ createDeclareVarExec(variableName.get, currVariable)
+
+ case ForState.VariableAssignment =>
+ state = ForState.Body
+ body.reset()
+ createSetVarExec(variableName.get, currVariable)
+
+ case ForState.Body =>
+ val retStmt = body.getTreeIterator.next()
+
+ // Handle LEAVE or ITERATE statement if it has been encountered.
+ retStmt match {
+ case leaveStatementExec: LeaveStatementExec if
!leaveStatementExec.hasBeenMatched =>
+ if (label.contains(leaveStatementExec.label)) {
+ leaveStatementExec.hasBeenMatched = true
+ }
+ interrupted = true
+ return retStmt
+ case iterStatementExec: IterateStatementExec if
!iterStatementExec.hasBeenMatched =>
+ if (label.contains(iterStatementExec.label)) {
+ iterStatementExec.hasBeenMatched = true
+ }
+ currRow += 1
+ state = ForState.VariableDeclaration
+ return retStmt
+ case _ =>
+ }
+
+ if (!body.getTreeIterator.hasNext) {
+ currRow += 1
+ state = ForState.VariableDeclaration
+ }
+ retStmt
+ }
+ }
+
+ /**
+ * Creates a Catalyst expression from Scala value.
+ */
+ private def createExpressionFromValue(value: Any): Expression = value match {
+ case m: Map[_, _] =>
+ // arguments of CreateMap are in the format: (key1, val1, key2, val2,
...)
+ val mapArgs = m.keys.toSeq.flatMap { key =>
+ Seq(createExpressionFromValue(key), createExpressionFromValue(m(key)))
+ }
+ CreateMap(mapArgs, false)
+ case s: GenericRowWithSchema =>
+ // struct types match this case
+ // arguments of CreateNamedStruct are in the format: (name1, val1, name2,
val2, ...)
+ val namedStructArgs = s.schema.names.toSeq.flatMap { colName =>
+ val valueExpression = createExpressionFromValue(s.getAs(colName))
+ Seq(Literal(colName), valueExpression)
+ }
+ CreateNamedStruct(namedStructArgs)
+ case _ => Literal(value)
Review Comment:
for my knowledge, can you explain what does the case with the `Map` means
exactly, i.e. when will this happen?
also, how did we check that this is the complete list of the relevant cases?
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