[GitHub] [spark] cloud-fan commented on a diff in pull request #37334: [SPARK-39887][SQL] RemoveRedundantAliases should keep attributes of a Union's first child

[GitBox <gi...@apache.org>]

cloud-fan commented on code in PR #37334:
URL: https://github.com/apache/spark/pull/37334#discussion_r934136325


##########
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala:
##########
@@ -568,9 +581,6 @@ object RemoveRedundantAliases extends Rule[LogicalPlan] {
           newChild
         }
 
-        // Create the attribute mapping. Note that the currentNextAttrPairs can contain duplicate
-        // keys in case of Union (this is caused by the PushProjectionThroughUnion rule); in this
-        // case we use the first mapping (which should be provided by the first child).

Review Comment:
   since we remove this comment, shall we add an assert to make sure there is no duplicate keys?



-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org


---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscribe@spark.apache.org
For additional commands, e-mail: reviews-help@spark.apache.org