Github user ConeyLiu commented on a diff in the pull request:
https://github.com/apache/spark/pull/19511#discussion_r145041400
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
---
@@ -890,32 +890,39 @@ class Analyzer(
/**
* Returns true if `exprs` contains a [[Star]].
+ * @param deepInto Whether to traverse all the subtrees, true by
default.
*/
- def containsStar(exprs: Seq[Expression]): Boolean =
- exprs.exists(_.collect { case _: Star => true }.nonEmpty)
+ def containsStar(exprs: Seq[Expression], deepInto: Boolean = true):
Boolean = {
+ if (deepInto) {
+ exprs.exists(_.collect { case _: Star => true }.nonEmpty)
+ } else {
+ exprs.exists{ case _: Star => true}
+ }
+ }
+
/**
* Expands the matching attribute.*'s in `child`'s output.
*/
def expandStarExpression(expr: Expression, child: LogicalPlan):
Expression = {
expr.transformUp {
- case f1: UnresolvedFunction if containsStar(f1.children) =>
+ case f1: UnresolvedFunction if containsStar(f1.children, false) =>
--- End diff --
And aslo I have question: whether we could combine the two traverse into
one ? Currently, we first need travese the `children` to test whether there is
a `Star`, and then we traverse another one to expand it. We have to go through
at least once, and need twice for existed.
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