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https://issues.apache.org/jira/browse/HIVE-23443?focusedWorklogId=439141&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-439141
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ASF GitHub Bot logged work on HIVE-23443:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 30/May/20 19:40
            Start Date: 30/May/20 19:40
    Worklog Time Spent: 10m 
      Work Description: pgaref closed pull request #1013:
URL: https://github.com/apache/hive/pull/1013


   


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Issue Time Tracking
-------------------

    Worklog Id:     (was: 439141)
    Time Spent: 1h 10m  (was: 1h)

> LLAP speculative task pre-emption seems to be not working
> ---------------------------------------------------------
>
>                 Key: HIVE-23443
>                 URL: https://issues.apache.org/jira/browse/HIVE-23443
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Prasanth Jayachandran
>            Assignee: Prasanth Jayachandran
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 4.0.0
>
>         Attachments: HIVE-23443.1.patch, HIVE-23443.2.patch, 
> HIVE-23443.3.patch
>
>          Time Spent: 1h 10m
>  Remaining Estimate: 0h
>
> I think after HIVE-23210 we are getting a stable sort order and it is causing 
> pre-emption to not work in certain cases.
> {code:java}
> "attempt_1589167813851_0000_119_01_000008_0 
> (hive_20200511055921_89598f09-19f1-4969-ab7a-82e2dd796273-119/Map 1, started 
> at 2020-05-11 05:59:22, in preemption queue, can finish)", 
> "attempt_1589167813851_0008_84_01_000008_1 
> (hive_20200511055928_7ae29ca3-e67d-4d1f-b193-05651023b503-84/Map 1, started 
> at 2020-05-11 06:00:23, in preemption queue, can finish)" {code}
> Scheduler only peek's at the pre-emption queue and looks at whether it is 
> non-finishable. 
> [https://github.com/apache/hive/blob/master/llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/TaskExecutorService.java#L420]
> In the above case, all tasks are speculative but state change is not 
> triggering pre-emption queue re-ordering so peek() always returns canFinish 
> task even though non-finishable tasks are in the queue. 



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