[jira] [Assigned] (TEZ-1447) Handle parallelism updates and versioning w/ custom InputInitializerEvents

["Bikas Saha (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TEZ-1447?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Bikas Saha reassigned TEZ-1447:
-------------------------------

    Assignee: Bikas Saha

> Handle parallelism updates and versioning w/ custom InputInitializerEvents
> --------------------------------------------------------------------------
>
>                 Key: TEZ-1447
>                 URL: https://issues.apache.org/jira/browse/TEZ-1447
>             Project: Apache Tez
>          Issue Type: Bug
>    Affects Versions: 0.5.0
>            Reporter: Gunther Hagleitner
>            Assignee: Bikas Saha
>            Priority: Blocker
>             Fix For: 0.5.0
>
>
> I'm trying to do dynamic partition pruning through input initializer events in Hive. That means that the initializer of a table scan vertex has to receive events from all tasks in another vertex (which contain the pruning info) before generating tasks to run.
> The problem with the current API I ran into:
> getNumTasks: I'm currently using a busy loop to wait for the num tasks for a vertex to be decided (-1 -> x). There's no way around it, because it's the only way to find out what number of events to expect (0 is a valid number of tasks - so I can't wait for the first to complete).
> With auto-reducer parallelism I have to employ another busy loop. Because I might be initially expecting 10 events, which later get's knocked down to 5. Since there's no event associated with this, I have to periodically check whether I have enough events.
> Versioning: Events have a version number, but I don't know which task they are coming from. Thus I can't de-dup events.



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