Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/4625#discussion_r137225205
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/rules/datastream/DataStreamWindowJoinRule.scala
---
@@ -55,8 +55,10 @@ class DataStreamWindowJoinRule
if (windowBounds.isDefined) {
if (windowBounds.get.isEventTime) {
- // we cannot handle event-time window joins yet
- false
+ val procTimeAttrInOutput = join.getRowType.getFieldList.asScala
+ .exists(f => FlinkTypeFactory.isProctimeIndicatorType(f.getType))
+
+ !remainingPredsAccessTime && !procTimeAttrInOutput
--- End diff --
No, the problem is that these rowtime attributes after a proc-time join
won't be aligned with the watermarks anymore. We would need to hold back
watermarks based on the data in the caches and not based on the window
boundaries.
Keeping the proctime attributes is fine because they are not bound to
watermarks.
---
