[
https://issues.apache.org/jira/browse/HBASE-17177?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15701071#comment-15701071
]
ramkrishna.s.vasudevan commented on HBASE-17177:
------------------------------------------------
bq.I do not think a region can be moved if there is major compaction running
for its storefiles?
Then its fine. I know this is how it was long back but off late I am not aware
of the changes to the assignments/region movements. So it is fine then.
> 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 kept.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
