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  1. Flink
  2. FLINK-18112 Approximate Task-Local Recovery -- Milestone One
  3. FLINK-20048

Make Approximate Local Recovery Compatible With PipelinedRegionSchedulingStrategy

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    • Sub-task
    • Status: Open
    • Major
    • Resolution: Unresolved
    • 1.12.0
    • None
    • Runtime / Coordination
    • None

    Description

      in the case where approximate_failover is enabled, only source task is scheduled to be deployed, and consumer tasks never deployed. So I guess it may be related to how the region is used in the region PipelinedRegionSchedulingStrategy.

      • For pipeline_(bounded), all vertices connected are considered as one region; there are not any dependent relations between regions, so PipelinedRegionSchedulingStrategy works roughly the same as EagerSchedulingStrategy
      • For blocking, regions are scheduled after dependent regions’ produced partitions are consumable.
      • From this point, it sounds like PipelinedRegionSchedulingStrategy should also work for pipeline_(approximate), but depends on how “produced partitions are consumable” is notified.

      The current version of how “produced partitions are consumable” is notified is very “blocking” specific.

      consumerRegions are maybe scheduled upon
      PipelinedRegionSchedulingStrategy#onExecutionStateChange
      First of all, it needs the “executionState == ExecutionState.FINISHED”;
      Second, only FINISHED and FAILED are notifiable in SchedulerBase#updateTaskExecutionState
      and e.t.c.

      I think if we make the “produced partitions are consumable” notification propagated properly for pipeline_approximated, it should work with pipeline_approximated as well.

      But the question is whether it is worthing the change? Because later, we probably won’t make each task in approximate mode a region after it has its own restart strategy?

      In short, the reason is approximate failover is restarted regionally but expected to be deployed as one region (if connected).

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            Unassigned Unassigned
            ym Yuan Mei
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              Created:
              Updated: