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Hudson commented on MAPREDUCE-6485: ----------------------------------- FAILURE: Integrated in Hadoop-trunk-Commit #8554 (See [https://builds.apache.org/job/Hadoop-trunk-Commit/8554/]) MAPREDUCE-6485. Create a new task attempt with failed map task priority (rohithsharmaks: rev 439f43ad3defbac907eda2d139a793f153544430) * hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/test/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TestTaskImpl.java * hadoop-mapreduce-project/CHANGES.txt * hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskImpl.java * hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-app/src/main/java/org/apache/hadoop/mapreduce/v2/app/job/impl/TaskAttemptImpl.java > MR job hanged forever because all resources are taken up by reducers and the > last map attempt never get resource to run > ----------------------------------------------------------------------------------------------------------------------- > > Key: MAPREDUCE-6485 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-6485 > Project: Hadoop Map/Reduce > Issue Type: Bug > Components: applicationmaster > Affects Versions: 3.0.0, 2.4.1, 2.6.0, 2.7.1 > Reporter: Bob > Assignee: Xianyin Xin > Priority: Critical > Fix For: 2.8.0 > > Attachments: MAPREDUCE-6485.001.patch, MAPREDUCE-6485.004.patch, > MAPREDUCE-6485.005.patch, MAPREDUCE-6485.006.patch, MAPREDUCE-6845.002.patch, > MAPREDUCE-6845.003.patch > > > The scenarios is like this: > With configuring mapreduce.job.reduce.slowstart.completedmaps=0.8, reduces > will take resource and start to run when all the map have not finished. > But It could happened that when all the resources are taken up by running > reduces, there is still one map not finished. > Under this condition , the last map have two task attempts . > As for the first attempt was killed due to timeout(mapreduce.task.timeout), > and its state transitioned from RUNNING to FAIL_CONTAINER_CLEANUP then to > FAILED, but failed map attempt would not be restarted for there is still one > speculate map attempt in progressing. > As for the second attempt which was started due to having enable map task > speculative is pending at UNASSINGED state because of no resource available. > But the second map attempt request have lower priority than reduces, so > preemption would not happened. > As a result all reduces would not finished because of there is one map left. > and the last map hanged there because of no resource available. so, the job > would never finish. -- This message was sent by Atlassian JIRA (v6.3.4#6332)