Github user bowenli86 commented on a diff in the pull request:
https://github.com/apache/flink/pull/4665#discussion_r140564281
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/runtime/operators/windowing/WindowOperator.java
---
@@ -405,6 +411,8 @@ public void merge(W mergeResult,
// windowAssigner is event time and current timestamp + allowed
lateness no less than element timestamp
if (isSkippedElement && lateDataOutputTag != null &&
isElementLate(element)) {
--- End diff --
the if-else conditions are duplicated and inefficient, and can be further
combined as
```java
if(isSkippedElement && isElementLate(element)) {
if(lateDataOutputTag != null) {
sideOutput(element);
}
this.lostDataCount.inc();
}
```
---
