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Panagiotis Garefalakis commented on HIVE-23443: ----------------------------------------------- Btw tried to capture the scenario in a test-case here: [https://github.com/apache/hive/pull/1013/files] feel free to use it > 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 > Attachments: HIVE-23443.1.patch > > > 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. -- This message was sent by Atlassian Jira (v8.3.4#803005)