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https://issues.apache.org/jira/browse/TEZ-1539?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Siddharth Seth updated TEZ-1539:
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    Attachment: TEZ-1539.5_branch05.txt

Rebased patch for branch 0.5

> Change InputInitializerEvent semantics to SEND_ONCE_ON_SUCCESS
> --------------------------------------------------------------
>
>                 Key: TEZ-1539
>                 URL: https://issues.apache.org/jira/browse/TEZ-1539
>             Project: Apache Tez
>          Issue Type: Improvement
>            Reporter: Siddharth Seth
>            Assignee: Siddharth Seth
>         Attachments: TEZ-1539.1.wip.txt, TEZ-1539.2.txt, TEZ-1539.3.txt, 
> TEZ-1539.4.txt, TEZ-1539.5.txt, TEZ-1539.5_branch05.txt
>
>
> Specifically for InputInitalizerEvents and VertexManagerEvents.
> Pasting comment from TEZ-1447
> In a majority of cases, events generated by different attempts of the same 
> task will be identical - in which case just making use of the event generated 
> by the first successful attempt is adequate. Doing something like this manes 
> that users don't worry about retries, indices etc - and can just rely on 
> receiving a set of events which are to be processed once the vertex succeeds.
> If different attempts of the same workload generate different events - 
> processing is likely to be incorrect, since it's very possible for all data 
> to be processed (VERTEX successful), then a failure and retry - which 
> generates a different event. The initializer doesn't even run at this point, 
> since it's already done it's work and is complete. Handling such scenarios, 
> likely involves re-running the entire initializer and re-starting the vertex 
> which processed the event from scratch. In situations like this, where data 
> generated may be different, the best bet is for speculation to be disabled 
> (when it's supported), and max-attempts to be set to 1.



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