Github user twalthr commented on a diff in the pull request: https://github.com/apache/flink/pull/5327#discussion_r188531694 --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/datastream/DataStreamJoin.scala --- @@ -60,6 +60,9 @@ class DataStreamJoin( override def needsUpdatesAsRetraction: Boolean = true + // outer join will generate retractions + override def producesRetractions: Boolean = joinType != JoinRelType.INNER --- End diff -- Thanks, now I understand the terminology between producing and just forwarding retractions.
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