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https://issues.apache.org/jira/browse/HBASE-5403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13208752#comment-13208752
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Li Pi commented on HBASE-5403:
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Rolling the log would just reset the dictionary, which means performance will
be degraded for a bit until the dictionary was built back up again.
I'm assuming checkpointing would involve dumping the contents of the dictionary
at certain points - but the max size of the dictionary can be quite large, up
to 32 megabytes or so in extreme cases. This has its own problems.
> Checkpoint the compressed HLog
> ------------------------------
>
> Key: HBASE-5403
> URL: https://issues.apache.org/jira/browse/HBASE-5403
> Project: HBase
> Issue Type: Improvement
> Reporter: Liyin Tang
> Assignee: Liyin Tang
>
> Let's assume that HBase replication can be based on replaying the HLog in the
> replica cluster.
> The replica process could be crash during the replay. Obviously, the replica
> process need a way to start from the lastest check point in the HLog, even
> the HLog is compressed.
> So the proposal is to write a series of checkpoints within the HLog.
> Each each checkpoint will have a header with some special sequence of bytes.
> And between each checkpoints, HLog should use new dictionaries to compress.
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