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https://issues.apache.org/jira/browse/HBASE-11315?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14050374#comment-14050374
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Jeffrey Zhong commented on HBASE-11315:
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Well said, [[email protected]]! It's hard to justify the cost keeping them
in FS is small for all use cases so let's keep current configurable way then.
If you're fine with the patch(besides the name), I'll commit the patch by the
end of today. Thanks.
> Keeping MVCC for configurable longer time
> ------------------------------------------
>
> Key: HBASE-11315
> URL: https://issues.apache.org/jira/browse/HBASE-11315
> Project: HBase
> Issue Type: Improvement
> Affects Versions: 0.99.0
> Reporter: Jeffrey Zhong
> Assignee: Jeffrey Zhong
> Attachments: hbase-11315.patch
>
>
> After hbase-8763, we need keep mvcc number longer in hfile so that it can be
> used to order changes during writes. For example, the known
> put,delete,put,... scenario, cross region server scan, out of order puts(in
> recovery case).
> Current thinking is that we make the retention period configurable(below
> we're using 1 day to explain). During major compaction, we check hfile's
> creation time if a hfile creation time is older than 1 day then all mvcc of
> KVs in that hfile will be removed. If a hfile is created within 1 day, then
> all mvccs of KVs in that hfile will be kept.
> In case there are time clock skew, we can firstly sort hfiles based on its
> seqId in ascending order and find the first hfile's creation time stamp less
> than 1 day. Then mvcc of all hfiles before the found file will be removed
> during compaction.
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