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https://issues.apache.org/jira/browse/KAFKA-9611?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Neil Green updated KAFKA-9611:
------------------------------
Description:
I've run into what appears to be undesirable behaviour in a streams app.
I have a KTable produced from a topic. The table contains entries like
"abc1234/signal1" : 1, "abc1234/signal2" : 3
The key is "id/signal name" and the value is an int. I want to produce a
aggregate ktable containing the sum all of the
signals for a given id.
{{So if source ktable contains:}}
{{+------------------+--+}}
{{| abc1234/signal1 | 2 |}}
{{| abc1234/signal2 | 4 |}}
{{| abc4566/signal1 | 3 |}}
{{+------------------+--+}}
{{Then the output should contain}}
{{+----------+--+}}
{{| abc1234 | 6 |}}
{{| abc4566 | 3 |}}
{{+----------+--+}}
{{On a change}}
{{+------------------+--+}}
{{| abc1234/signal1 | 3 |}}
{{+------------------+--+}}
{{```}}
{{I would expect the change}}
{{```}}
{{+----------+--+}}
{{| abc1234 | 7 |}}
{{+----------+--+}}
{{to be published.}}
In fact there are two changelog entries published
{{+----------+--+}}
{{| abc1234 | 4 | // This is incorrect. The sum of the signals is never 4.}}
{{+----------+--+}}
Then
{{+----------+--+}}
{{| abc1234 | 7 |}}
{{+----------+--+}}
was:
I've run into what appears to be strange behaviour in a streams app.
I have a KTable produced from a topic. The table contains entries like
"abc1234/signal1" : 1, "abc1234/signal2" : 3
The key is "id/signal name" and the value is an int. I want to produce a
aggregate ktable containing the sum all of the
signals for a given id.
{{So if source ktable contains:}}
{{+-----------------+---+}}
{{| abc1234/signal1 | 2 |}}
{{| abc1234/signal2 | 4 |}}
{{| abc4566/signal1 | 3 |}}
{{+-----------------+---+}}
{{Then the output should contain}}
{{+---------+---+}}
{{| abc1234 | 6 |}}
{{| abc4566 | 3 |}}
{{+---------+---+}}
{{On a change}}
{{+-----------------+---+}}
{{| abc1234/signal1 | 3 |}}
{{+-----------------+---+}}
{{```}}
{{I would expect the change}}
{{```}}
{{+---------+---+}}
{{| abc1234 | 7 |}}
{{+---------+---+}}
{{to be published.}}
In fact there are two changelog entries published
{{+---------+---+}}
{{| abc1234 | 4 | // This is incorrect. The sum of the signals is never 4.}}
{{+---------+---+}}
Then
{{+---------+---+}}
{{| abc1234 | 7 |}}
{{+---------+---+}}
> KGroupedTable.aggregate(...) emits incorrect values
> ---------------------------------------------------
>
> Key: KAFKA-9611
> URL: https://issues.apache.org/jira/browse/KAFKA-9611
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.4.0
> Reporter: Neil Green
> Priority: Major
>
> I've run into what appears to be undesirable behaviour in a streams app.
> I have a KTable produced from a topic. The table contains entries like
> "abc1234/signal1" : 1, "abc1234/signal2" : 3
> The key is "id/signal name" and the value is an int. I want to produce a
> aggregate ktable containing the sum all of the
> signals for a given id.
> {{So if source ktable contains:}}
> {{+------------------+--+}}
> {{| abc1234/signal1 | 2 |}}
> {{| abc1234/signal2 | 4 |}}
> {{| abc4566/signal1 | 3 |}}
> {{+------------------+--+}}
> {{Then the output should contain}}
> {{+----------+--+}}
> {{| abc1234 | 6 |}}
> {{| abc4566 | 3 |}}
> {{+----------+--+}}
> {{On a change}}
> {{+------------------+--+}}
> {{| abc1234/signal1 | 3 |}}
> {{+------------------+--+}}
> {{```}}
> {{I would expect the change}}
> {{```}}
> {{+----------+--+}}
> {{| abc1234 | 7 |}}
> {{+----------+--+}}
> {{to be published.}}
> In fact there are two changelog entries published
> {{+----------+--+}}
> {{| abc1234 | 4 | // This is incorrect. The sum of the signals is never 4.}}
> {{+----------+--+}}
> Then
> {{+----------+--+}}
> {{| abc1234 | 7 |}}
> {{+----------+--+}}
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