Github user hequn8128 commented on a diff in the pull request:
https://github.com/apache/flink/pull/4471#discussion_r158489035
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/util/UpdatingPlanChecker.scala
---
@@ -116,14 +135,100 @@ object UpdatingPlanChecker {
val windowStartEnd = w.getWindowProperties.map(_.name)
// we have only a unique key if at least one window property is
selected
if (windowStartEnd.nonEmpty) {
- keys = Some(groupKeys ++ windowStartEnd)
+ val smallestAttribute = windowStartEnd.sorted.head
--- End diff --
Thanks, `windowStartEnd.min` is better, i want to get the lexicographic
smallest attribute from `windowStartEnd` . I have sorted it before get the
first string.
---
