Github user maropu commented on a diff in the pull request:
https://github.com/apache/spark/pull/19977#discussion_r158942832
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/expressions.scala
---
@@ -645,11 +646,16 @@ object CombineConcats extends Rule[LogicalPlan] {
stack.pop() match {
case Concat(children) =>
stack.pushAll(children.reverse)
+ case Cast(Concat(children), StringType, _) =>
--- End diff --
Ah, I see. But, IIUC there is no chance where all the children of `Concat`
have `Cast`s. If all inputs of `Concat` are binary, the parent `Concat` just
concats binary inputs into a binary output (In this case, children need no
`Cast`).
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
