[
https://issues.apache.org/jira/browse/HIVE-23443?focusedWorklogId=433984&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-433984
]
ASF GitHub Bot logged work on HIVE-23443:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 16/May/20 01:19
Start Date: 16/May/20 01:19
Worklog Time Spent: 10m
Work Description: prasanthj commented on a change in pull request #1012:
URL: https://github.com/apache/hive/pull/1012#discussion_r426102275
##########
File path:
llap-server/src/java/org/apache/hadoop/hive/llap/daemon/impl/TaskExecutorService.java
##########
@@ -884,10 +885,20 @@ private void finishableStateUpdated(TaskWrapper
taskWrapper, boolean newFinishab
taskWrapper.updateCanFinishForPriority(newFinishableState);
forceReinsertIntoQueue(taskWrapper, isRemoved);
} else {
- taskWrapper.updateCanFinishForPriority(newFinishableState);
- if (!newFinishableState && !taskWrapper.isInPreemptionQueue()) {
- // No need to check guaranteed here; if it was false we would
already be in the queue.
+ // if speculative task, any finishable state change should re-order
the queue as speculative tasks are always
+ // not-guaranteed (re-order helps put non-finishable's ahead of
finishable)
+ if (!taskWrapper.isGuaranteed()) {
+ removeFromPreemptionQueue(taskWrapper);
+ taskWrapper.updateCanFinishForPriority(newFinishableState);
addToPreemptionQueue(taskWrapper);
+ } else {
+ // if guaranteed task, if the finishable state changed to
non-finishable and if the task doesn't exist
+ // pre-emption queue, then add it so that it becomes candidate to
kill
+ taskWrapper.updateCanFinishForPriority(newFinishableState);
Review comment:
Non-finishable -> Finishable does not have to be pre-emption queue. This
could be in wait queue (if not capacity) or taken by executor to run both of
which are fine.
You brought up good point, we may be adding the same task fragment to
pre-emption queue twice. I will add a "if not exists" check when adding to
pre-emption queue.
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Issue Time Tracking
-------------------
Worklog Id: (was: 433984)
Time Spent: 40m (was: 0.5h)
> 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
> Attachments: HIVE-23443.1.patch, HIVE-23443.2.patch
>
> Time Spent: 40m
> 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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