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https://issues.apache.org/jira/browse/TEZ-1447?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14101297#comment-14101297
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Bikas Saha commented on TEZ-1447:
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The events will be routed to you because the events say so. The events say so
because the user generated them that way. The only reason you would get an
unexpected event is when the user code at the source is incorrectly asking the
system to send them to your initializer.
> 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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