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https://issues.apache.org/jira/browse/KAFKA-10493?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17329387#comment-17329387
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Bruno Cadonna commented on KAFKA-10493:
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Good point about the compaction!
{quote}Sounds like a step backwards?
{quote}
What is worse not dropping out-of-order records or not having the source topic
optimization? It seems like they are not compatible.
{quote}After
[KIP-280|https://cwiki.apache.org/confluence/display/KAFKA/KIP-280%3A+Enhanced+log+compaction]
is done, we could drop out-or-order records also with source-table
materialization enabled.
{quote}
Streams does not have control over the source topic. So even if KIP-280 is
done, Streams cannot impose a compaction strategy on the source topic.
{quote}Topology optimization is already disabled by default.
{quote}
I know. that was just to state the defaults in the case of per-table knobs. Of
course, I would regard the knobs for source topic optimization and dropping
out-of-order records as expert mode.
> KTable out-of-order updates are not being ignored
> -------------------------------------------------
>
> Key: KAFKA-10493
> URL: https://issues.apache.org/jira/browse/KAFKA-10493
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.6.0
> Reporter: Pedro Gontijo
> Assignee: Matthias J. Sax
> Priority: Blocker
> Fix For: 3.0.0
>
> Attachments: KTableOutOfOrderBug.java
>
>
> On a materialized KTable, out-of-order records for a given key (records which
> timestamp are older than the current value in store) are not being ignored
> but used to update the local store value and also being forwarded.
> I believe the bug is here:
> [https://github.com/apache/kafka/blob/2.6.0/streams/src/main/java/org/apache/kafka/streams/state/internals/ValueAndTimestampSerializer.java#L77]
> It should return true, not false (see javadoc)
> The bug impacts here:
> [https://github.com/apache/kafka/blob/2.6.0/streams/src/main/java/org/apache/kafka/streams/kstream/internals/KTableSource.java#L142-L148]
> I have attached a simple stream app that shows the issue happening.
> Thank you!
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