[jira] (KAFKA-15417) JoinWindow does not seem to work properly with a KStream - KStream - LeftJoin()

["Victor van den Hoven (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-15417 ]


    Victor van den Hoven deleted comment on KAFKA-15417:
    ----------------------------------------------

was (Author: victorvandenhoven):
The before/after for the joinSpuriousLookBackTimeMs in the left/right join node were flipped indeed.
After setting them correctly all unit tests still continued to pass, because there were no unit tests available for leftJoin scenario's.

So I added two leftJoin tests:  one for leftJoin with joined items and one for left-join with null-joined items.

All tests seem to  work successfully and also my own application works as expected.

Shall I create the PR?

 

> JoinWindow does not  seem to work properly with a KStream - KStream - LeftJoin()
> --------------------------------------------------------------------------------
>
>                 Key: KAFKA-15417
>                 URL: https://issues.apache.org/jira/browse/KAFKA-15417
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>    Affects Versions: 3.4.0
>            Reporter: Victor van den Hoven
>            Assignee: Victor van den Hoven
>            Priority: Major
>         Attachments: SimpleStreamTopology.java, SimpleStreamTopologyTest.java
>
>
> In Kafka-streams 3.4.0 :
> According to the javadoc of the Joinwindow:
> _There are three different window configuration supported:_
>  * _before = after = time-difference_
>  * _before = 0 and after = time-difference_
>  * _*before = time-difference and after = 0*_
>  
> However if I use a joinWindow with *before = time-difference and after = 0* 
> on a kstream-kstream-leftjoin the *after=0* part does not seem to work.
> When using _stream1.leftjoin(stream2, joinWindow)_ with {_}joinWindow{_}.{_}after=0 and joinWindow.before=30s{_}, any new message on stream 1 that can not be joined with any messages on stream2 should be joined with a null-record after the _joinWindow.after_ has ended and a new message has arrived on stream1.
> It does not.
> Only if the new message arrives after the value of _joinWindow.before_ the previous message will be joined with a null-record.
>  
> Attached you can find two files with a TopologyTestDriver Unit test to reproduce.
> topology:   stream1.leftjoin( stream2, joiner, joinwindow)
> joinWindow has before=5000ms and after=0
> message1(key1) ->  stream1
> after 4000ms message2(key2) -> stream1  ->  NO null-record join was made, but the after period was expired.
> after 4900ms message2(key2) -> stream1  ->  NO null-record join was made, but the after period was expired.
> after 5000ms message2(key2) -> stream1  ->  A null-record join was made,  before period was expired.
> after 6000ms message2(key2) -> stream1  ->  A null-record join was made,  before period was expired.
>  



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