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https://issues.apache.org/jira/browse/KAFKA-20035?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18063334#comment-18063334
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S. Sikka commented on KAFKA-20035:
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We also think this is valid concern that should be addressed. 
During production workloads, increasing partitions due to organic growth or new 
launches causes messages to be silently skipped with 
{{{}auto.offset.reset=latest{}}}, since no committed offset exists for the new 
partitions. As a workaround, for critical production workloads we've often set 
to use {{earliest}} with high retention times purely to guard against this , 
which adds unnecessary reprocessing overhead and storage costs.

> Prevent data loss during partition expansion by enforcing "earliest" offset 
> reset for dynamically added partitions
> ------------------------------------------------------------------------------------------------------------------
>
>                 Key: KAFKA-20035
>                 URL: https://issues.apache.org/jira/browse/KAFKA-20035
>             Project: Kafka
>          Issue Type: Bug
>          Components: clients, consumer, core, group-coordinator
>            Reporter: Chia-Ping Tsai
>            Assignee: Ken Huang
>            Priority: Critical
>              Labels: kip
>
> Currently, when a consumer group is configured with {{{}auto.offset.reset = 
> latest{}}}, dynamically adding new partitions to a subscribed topic can lead 
> to data loss due to a race condition.
> The scenario is as follows:
>  # A group subscribes to a topic with {{{}auto.offset.reset = latest{}}}.
>  # The topic is expanded (e.g., from 3 to 4 partitions).
>  # Producers immediately start writing data to the new partition (Partition 
> 3).
>  # The Group Coordinator detects the change and assigns Partition 3 to a 
> member.
>  # The member initializes the partition. Since there is no committed offset, 
> it applies the
>  # *Result: Any messages written to Partition 3 between step 3 and step 5 are 
> skipped and lost.*
> From a user's perspective, {{latest}} should mean "start consuming from the 
> point of subscription," not "skip data from newly created infrastructure."
> KIP-1282: 
> [https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=406619800] 



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