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https://issues.apache.org/jira/browse/HBASE-17177?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15698034#comment-15698034
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Duo Zhang commented on HBASE-17177:
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[~stack] [~ram_krish] Is the description clear enough?
And for the solution, maybe we could disable major compaction for a small
amount when the region is just online? Maybe several minutes?
Thanks.
> Major compaction can break the region/row level atomic when scan even if we
> pass mvcc to client
> -----------------------------------------------------------------------------------------------
>
> Key: HBASE-17177
> URL: https://issues.apache.org/jira/browse/HBASE-17177
> Project: HBase
> Issue Type: Sub-task
> Components: scan
> Reporter: Duo Zhang
> Fix For: 2.0.0, 1.4.0
>
>
> We know that major compaction will actually delete the cells which are
> deleted by a delete marker. In order to give a consistent view for a scan, we
> need to use a map to track the read points for all scanners for a region, and
> the smallest one will be used for a compaction. For all delete markers whose
> mvcc is greater than this value, we will not use it to delete other cells.
> And the problem for a scan restart after region move is that, the new RS does
> not have the information of the scanners opened at the old RS before the
> client sends scan requests to the new RS which means the read points map is
> incomplete and the smallest read point maybe greater than the correct value.
> So if a major compaction happens at that time, it may delete some cells which
> should be keeped.
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