Etienne Chauchot created FLINK-22587:
----------------------------------------
Summary: Support aggregations in batch mode with DataStream API
Key: FLINK-22587
URL: https://issues.apache.org/jira/browse/FLINK-22587
Project: Flink
Issue Type: Improvement
Components: API / DataStream
Reporter: Etienne Chauchot
A pipeline like this *in batch mode* would output no data
{code:java}
stream.join(otherStream)
.where(<KeySelector>)
.equalTo(<KeySelector>)
.window(GlobalWindows.create())
.apply(<JoinFunction>)
{code}
Indeed the default trigger for GlobalWindow is NeverTrigger which never fires.
If we set a _EventTimeTrigger_ it will fire with every element as the watermark
will be set to +INF (batch mode) and will pass the end of the global window
with each new element. A _ProcessingTimeTrigger_ never fires either and all
elapsed time or delta based triggers would not be suited for batch.
Same goes for _reduce()_ instead of join().
So I guess we miss something for batch support with DataStream.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
