[jira] [Updated] (TEZ-1539) Change InputInitializerEvent semantics to SEND_ONCE_ON_SUCCESS

["Siddharth Seth (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TEZ-1539?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Siddharth Seth updated TEZ-1539:
--------------------------------
    Summary: Change InputInitializerEvent semantics to SEND_ONCE_ON_SUCCESS  (was: Allow a FIRE_ONCE_ON_SUCCESS model for events generated by user code)

> 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
>
>
> 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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