[
https://issues.apache.org/jira/browse/MAPREDUCE-6622?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15182528#comment-15182528
]
zhihai xu commented on MAPREDUCE-6622:
--------------------------------------
Committed it to 2.8 also.
> Add capability to set JHS job cache to a task-based limit
> ---------------------------------------------------------
>
> Key: MAPREDUCE-6622
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6622
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: jobhistoryserver
> Affects Versions: 2.7.2
> Reporter: Ray Chiang
> Assignee: Ray Chiang
> Priority: Critical
> Labels: supportability
> Fix For: 2.8.0, 2.7.3, 2.9.0, 2.6.5
>
> Attachments: MAPREDUCE-6622.001.patch, MAPREDUCE-6622.002.patch,
> MAPREDUCE-6622.003.patch, MAPREDUCE-6622.004.patch, MAPREDUCE-6622.005.patch,
> MAPREDUCE-6622.006.patch, MAPREDUCE-6622.007.patch, MAPREDUCE-6622.008.patch,
> MAPREDUCE-6622.009.patch, MAPREDUCE-6622.010.patch, MAPREDUCE-6622.011.patch,
> MAPREDUCE-6622.012.patch, MAPREDUCE-6622.013.patch, MAPREDUCE-6622.014.patch
>
>
> When setting the property mapreduce.jobhistory.loadedjobs.cache.size the jobs
> can be of varying size. This is generally not a problem when the jobs sizes
> are uniform or small, but when the job sizes can be very large (say greater
> than 250k tasks), then the JHS heap size can grow tremendously.
> In cases, where multiple jobs are very large, then the JHS can lock up and
> spend all its time in GC. However, since the cache is holding on to all the
> jobs, not much heap space can be freed up.
> By setting a property that sets a cap on the number of tasks allowed in the
> cache and since the total number of tasks loaded is directly proportional to
> the amount of heap used, this should help prevent the JHS from locking up.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
