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Wangda Tan commented on MAPREDUCE-6302: --------------------------------------- Linked to YARN-1680, one is for more accurate calculation, one is to prevent inaccurate calculation. > deadlock in a job between map and reduce cores allocation > ---------------------------------------------------------- > > Key: MAPREDUCE-6302 > URL: https://issues.apache.org/jira/browse/MAPREDUCE-6302 > Project: Hadoop Map/Reduce > Issue Type: Bug > Affects Versions: 2.6.0 > Reporter: mai shurong > Assignee: Karthik Kambatla > Priority: Critical > Attachments: AM_log_head100000.txt.gz, AM_log_tail100000.txt.gz, > log.txt, mr-6302-prelim.patch, queue_with_max163cores.png, > queue_with_max263cores.png, queue_with_max333cores.png > > > I submit a big job, which has 500 maps and 350 reduce, to a > queue(fairscheduler) with 300 max cores. When the big mapreduce job is > running 100% maps, the 300 reduces have occupied 300 max cores in the queue. > And then, a map fails and retry, waiting for a core, while the 300 reduces > are waiting for failed map to finish. So a deadlock occur. As a result, the > job is blocked, and the later job in the queue cannot run because no > available cores in the queue. > I think there is the similar issue for memory of a queue . -- This message was sent by Atlassian JIRA (v6.3.4#6332)