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Siddharth Seth commented on TEZ-1447: ------------------------------------- Splitting this into two jiras - one for modifying the event itself to contain some src information, and retaining this one to send in relevant notifications. Given that we don't have any concept of Control Edges - Initializers will have to register for updates from specific Vertices; sending updates for all vertices in the DAG to all initializers would be a lot of unnecessary events. In any case, most of the changes should be common - if ever we add control edges. > 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: Siddharth Seth > Priority: Blocker > > 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. -- This message was sent by Atlassian JIRA (v6.3.4#6332)