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From "Anoop Sam John (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-10885) Support visibility expressions on Deletes
Date Thu, 01 May 2014 03:09:18 GMT

    [ https://issues.apache.org/jira/browse/HBASE-10885?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13986315#comment-13986315
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Anoop Sam John commented on HBASE-10885:
----------------------------------------

Yes as u said , without vis exp  the delete will remove all cells except ts=105
With vis exp in delete, the exact version delete should delete cell ts=104 as the vis exps
are matching. For deleteFamily case all cells with ts <=103 are candidates for delete but
u can see only one cell with ts=103 is having matching vis exp withh that in the delete cell.
Cells with ts 102 and 101 are not having matching vis exps and so should not be getting deleted.


> Support visibility expressions on Deletes
> -----------------------------------------
>
>                 Key: HBASE-10885
>                 URL: https://issues.apache.org/jira/browse/HBASE-10885
>             Project: HBase
>          Issue Type: Improvement
>    Affects Versions: 0.98.1
>            Reporter: Andrew Purtell
>            Assignee: ramkrishna.s.vasudevan
>            Priority: Blocker
>             Fix For: 0.99.0, 0.98.3
>
>         Attachments: HBASE-10885_1.patch, HBASE-10885_2.patch
>
>
> Accumulo can specify visibility expressions for delete markers. During compaction the
cells covered by the tombstone are determined in part by matching the visibility expression.
This is useful for the use case of data set coalescing, where entries from multiple data sets
carrying different labels are combined into one common large table. Later, a subset of entries
can be conveniently removed using visibility expressions.
> Currently doing the same in HBase would only be possible with a custom coprocessor. Otherwise,
a Delete will affect all cells covered by the tombstone regardless of any visibility expression
scoping. This is correct behavior in that no data spill is possible, but certainly could be
surprising, and is only meant to be transitional. We decided not to support visibility expressions
on Deletes to control the complexity of the initial implementation.



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