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https://issues.apache.org/jira/browse/HBASE-2673?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12876524#action_12876524
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Todd Lipcon commented on HBASE-2673:
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I thought about this a bit tonight. I think this is essentially impossible to
implement unless we do the following:
- Add logical timestamps to HFiles (a few bytes per KV if we use vints and
relative to an hfile-wide meta entry)
- Add to the scanner API so that each scan result object also returns the
current logical timestamp
- Add logical timestamps to HLog entries so that a server that replays the
edits maintains the same logical timestamps of each row.
I think these are all needed in order to maintain consistency in the face of
failure or through a flush operation.
Rather than do all of the above, I think we should simply document in
Scanner.setBatch that using intra-row scanning loses the consistency guarantee.
Also we'll want to augment the acid guarantees doc to state this.
> Investigate consistency of intra-row scans
> ------------------------------------------
>
> Key: HBASE-2673
> URL: https://issues.apache.org/jira/browse/HBASE-2673
> Project: HBase
> Issue Type: Task
> Components: documentation, regionserver
> Affects Versions: 0.21.0
> Reporter: Todd Lipcon
> Assignee: Todd Lipcon
>
> I have an intuition that intra-row scanning probably does not provide a
> consistent view of the row. We should investigate how true this is, and
> document what the interaction of the feature is with the guarantee, etc.
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