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https://issues.apache.org/jira/browse/KAFKA-1275?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13922944#comment-13922944
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Joe Stein commented on KAFKA-1275:
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I am a bit confused by
"3.The offset for a message never changes, it is the permanent identifier for a
position in the log.
4. Any read from offset 0 will contain see the final state of all records
provided it completes in less than a configurable time period (even if further
compaction occurs during this read).
The third guarantee seems somewhat esoteric but this ensures that a reader will
end in a coherent state (equivalent to reading the full uncompacted log) even
though the underlying log may be compacted while this read occurs"
shouldn't it be the fourth guarantee? I am not sure I understand number 4
(haven't looked at the code) does it mean you are reading the log and not the
copy of the log since you started prior to compaction ending?
Also does this mean now that the compaction could mean you might need ~ twice ~
as much disk space (assuming a scenario where almost the entire log is copied
(nothing not held back from writing)...
also the word "Offset" is missing from the diagram Log After Compaction.
lastly it is not entirely clear exactly what will happen when you turn
log.cleanup.policy=compact on for a topic, is there a specific class that gets
executed ? what gets deleted? how do you control it? or do you have to build a
compaction strategy or use an existing one?
> fixes for quickstart documentation
> ----------------------------------
>
> Key: KAFKA-1275
> URL: https://issues.apache.org/jira/browse/KAFKA-1275
> Project: Kafka
> Issue Type: Bug
> Components: website
> Affects Versions: 0.8.1
> Reporter: Evan Zacks
> Assignee: Jay Kreps
> Priority: Minor
> Labels: documentation
> Fix For: 0.8.1
>
> Attachments: KAFKA-1275-quickstart-doc.patch
>
>
> The quickstart guide refers to commands that no longer exist in the master
> git branch per changes in KAFKA-554.
> If changes for the documentation to match 0.8.1 are already in development
> elsewhere, please feel free to discard this issue.
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