Github user pnowojski commented on a diff in the pull request:
https://github.com/apache/flink/pull/4626#discussion_r136332646
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/functions/aggregation/PreAggregationOperator.java
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@@ -0,0 +1,249 @@
+/
Github user aljoscha commented on a diff in the pull request:
https://github.com/apache/flink/pull/4626#discussion_r136293381
--- Diff:
flink-streaming-java/src/main/java/org/apache/flink/streaming/api/functions/aggregation/PreAggregationOperator.java
---
@@ -0,0 +1,249 @@
+/*
GitHub user pnowojski opened a pull request:
https://github.com/apache/flink/pull/4626
[FLINK-7561][streaming] Implement PreAggregationOperator
## What is the purpose of the change
To improve performance in certain situations this PR adds basic
implementation of pre-aggrega
