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https://issues.apache.org/jira/browse/KAFKA-8522?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16902334#comment-16902334
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Jun Rao commented on KAFKA-8522:
--------------------------------

[~Yohan123], I was thinking of adding a new checkpoint file per partition. If 
we do that, we probably want to move the cleaning offset currently stored in 
the per disk log cleaner checkpoint file there and deprecate the per disk log 
cleaner checkpoint file.

> Tombstones can survive forever
> ------------------------------
>
>                 Key: KAFKA-8522
>                 URL: https://issues.apache.org/jira/browse/KAFKA-8522
>             Project: Kafka
>          Issue Type: Bug
>          Components: log cleaner
>            Reporter: Evelyn Bayes
>            Priority: Minor
>
> This is a bit grey zone as to whether it's a "bug" but it is certainly 
> unintended behaviour.
>  
> Under specific conditions tombstones effectively survive forever:
>  * Small amount of throughput;
>  * min.cleanable.dirty.ratio near or at 0; and
>  * Other parameters at default.
> What  happens is all the data continuously gets cycled into the oldest 
> segment. Old records get compacted away, but the new records continuously 
> update the timestamp of the oldest segment reseting the countdown for 
> deleting tombstones.
> So tombstones build up in the oldest segment forever.
>  
> While you could "fix" this by reducing the segment size, this can be 
> undesirable as a sudden change in throughput could cause a dangerous number 
> of segments to be created.



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