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https://issues.apache.org/jira/browse/SPARK-4167?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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SuYan closed SPARK-4167.
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Resolution: Not a Problem
> Schedule task on Executor will be Imbalance while task run less than
> local-wait time
> ------------------------------------------------------------------------------------
>
> Key: SPARK-4167
> URL: https://issues.apache.org/jira/browse/SPARK-4167
> Project: Spark
> Issue Type: Improvement
> Components: Spark Core
> Affects Versions: 1.1.0
> Reporter: SuYan
>
> Recently, when run a spark on yarn job. it occurs executor schedules
> imbalance.
> the procedure is that:
> 1. because user's mistake, the spark on yarn job's input split contains 0
> byte empty splits.
> 1.1:
> task0-99 , no-preference task(0 byte)
> task100-800, node-local task
> 1.2: user will run task 500 loops
> 1.3: 60 executor
> 2.
> executor A only have 2 node-local task in the first loop, executor A first
> finished node-local-task, the it will run no-preference task, and the
> no-preference task in our situation have smaller input split than node-local
> task. So executor A finished all no-reference task, while others still run
> node-local job.
> in the second loop, all task have process-local level, and all task finished
> in 3 seconds, so while executor A is still run process-local task while
> others are all finished process-local task. but all process-task run by
> executor A will finished in 3 seconds, so the local level will always be
> process-local.
> it results other executors are all wait for executor A the same situation in
> the left loops.
> To solve this situation, we let user to delete the empty input split.
> but is still have implied imbalance, while in some loops, a executor got
> more process-local task than others in one loop, and this task all less-3
> seconds task. and then in the left loops, the others executor will wait that
> executor to finished all process-local tasks.
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