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https://issues.apache.org/jira/browse/KAFKA-8613?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16936172#comment-16936172
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John Roesler commented on KAFKA-8613:
-------------------------------------
Hey [~cadonna],
I just learned of this ticket from the mention on KAFKA-8924. I initially
shared this viewpoint, but recently, I've started to wonder if `0` is actually
the right default grace period. It would mean that Streams by default would not
process late records (out-of-order data arriving after the window end) at all.
I believe the only instance in which our current default has been confusing is
when folks use Suppress in conjunction with the default grace period. Maybe we
can find a good, direct solution to that problem (like requiring an explicit
grace period when using Suppress) rather than dropping all late records for all
windowed aggregations.
Then again, you might have some other reason in mind to change the default. Can
you comment on the rationale?
Thanks,
-John
> Set default grace period to 0
> -----------------------------
>
> Key: KAFKA-8613
> URL: https://issues.apache.org/jira/browse/KAFKA-8613
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Bruno Cadonna
> Priority: Blocker
> Fix For: 3.0.0
>
>
> Currently, the grace period is set to retention time if the grace period is
> not specified explicitly. The reason for setting the default grace period to
> retention time was backward compatibility. Topologies that were implemented
> before the introduction of the grace period, added late arriving records to a
> window as long as the window existed, i.e., as long as its retention time was
> not elapsed.
> This unintuitive default grace period has already caused confusion among
> users.
> For the next major release, we should set the default grace period to
> {{Duration.ZERO}}.
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