Duo Zhang created HBASE-17177:
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             Summary: 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


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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