Always allow local blocks to be put #1
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An interesting failure happens when migrateDuring = true (and persist or shuffle is true): - We schedule the job with tasks on executors 0, 1, 2. - We wait 300 ms and decommission executor 0. - If the task is not yet done on executor 0, it will now fail because the block manager won't be able to save the block. This condition is easy to trigger on a loaded machine where the github checks run. - The task with retry on a different executor (1 or 2) and its shuffle blocks will land there. - No actual block migration happens here because the decommissioned executor technically failed before it could even produce a block. So this change makes two fixes to remove the above race condition. - When migrateDuring = true, wait for a task to complete and write the block, and then decommission that executor. - When migrateDuring = false, it is still possible (because of delay scheduling) for two tasks to be run on the same executor serially and one executor to go idle. In which case, we must make sure to decommission an executor that actually had a task run on it.
Now that we wait for an actual task to succeed, we don't need to wait for events prior to that: broadcast of job-info finished and task started. The waiting for the task end/success subsumes that. Simplifying the test even further.
…cal blocks from the BlockManager (useful in testing).
agrawaldevesh
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From our conversation, this changes the block manager to always allow local blocks to be put avoiding the race condition. Generally speaking this shouldn't matter in production but it should help avoid the test race condition.