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From "Ryan Leary (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-3044) ConditionalMutation should support conditional updates
Date Wed, 06 Aug 2014 15:22:12 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-3044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14087782#comment-14087782
] 

Ryan Leary commented on ACCUMULO-3044:
--------------------------------------

Keith, I will create some small example to get some actual timing numbers. I'll need to profile
to understand best where the additional time is being spent. Chris -- you're probably right
that such a change, if it were to be applied is no longer a 'mutation' by definition.

> ConditionalMutation should support conditional updates
> ------------------------------------------------------
>
>                 Key: ACCUMULO-3044
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3044
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: client, tserver
>    Affects Versions: 1.6.0
>            Reporter: Ryan Leary
>
> Currently, the ConditionalMutation object operates on a single row, and applies updates
if and only if a set of Conditions are met. 
> A new type of ConditionalMutation which operates on a single row and applies an update
if and only if a set of Conditions for that particular update would be more flexible.
> This behavior is possible currently by creating a new ConditionalMutation for each update.
In the case where there are a large number of updates for a single row, however, there is
a steep penalty paid due to the row-level locking. Another acceptable solution to this ticket
would be optimizing the ConditionalWriter to apply multiple conditional mutations on the same
row within the same atomic lock. The order of execution would need to be guaranteed.
> The API would look something like:
> {code}
> ConditionalMutation cm = new ConditionalMutation(rowKey);
> cm.put(Iterable<Condition>, CF, CQ, CV, Val);
> {code}



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