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Jonathan Eagles commented on TEZ-3935: -------------------------------------- This will improve the many type of jobs. Does this setting have any interactions with pre-warm containers? If so we should list that in the description as well. > DAG aware scheduler should release unassigned new containers rather than hold > them > ---------------------------------------------------------------------------------- > > Key: TEZ-3935 > URL: https://issues.apache.org/jira/browse/TEZ-3935 > Project: Apache Tez > Issue Type: Bug > Reporter: Jason Lowe > Assignee: Jason Lowe > Priority: Major > Attachments: TEZ-3935.001.patch > > > I saw a case for a very large job with many containers where the DAG aware > scheduler was getting behind on assigning containers. Newly assigned > containers were not finding any matching request, so they were queued for > reuse processing. However it took so long to get through all of the task and > container events that the container allocations expired before the container > was finally assigned and attempted to be launched. > Newly assigned containers are assigned to their matching requests, even if > that violates the DAG priorities, so it should be safe to simply release > these if no tasks could be found to use them. The matching request has > either been removed or already satisified with a reused container. Besides, > if we can't find any tasks to take the newly assigned container then it is > very likely we have plenty of reusable containers already, and keeping more > containers just makes the job a resource hog on the cluster. -- This message was sent by Atlassian JIRA (v7.6.3#76005)