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https://issues.apache.org/jira/browse/MAPREDUCE-3944?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13220342#comment-13220342
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Siddharth Seth commented on MAPREDUCE-3944:
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bq. There are two things that I can think of that can help make this faster.
The first one is to move as much filtering for the web service up to use
PartialJob where possible. This will allow us to not load as many full jobs.
The next one is that we need to fix the locking on getJob, so that we can be
loading more then one job at a time. we need to some how lock on the JobID and
not on the HistoryServer.
+1 for these two changes. JobHistory used to have a method which did filtering
on some parameters. That was removed a while ago - since it was never used. You
may want to pull out the history for JobHistory.java.
Considering the webservice ends up building CompletedJob objects for each job
that it has to return - it can grow much bigger than the configured
CompletedJobCache size and can cause the JobHistory server to go OOM.
MAPREDUCE-3755 will help towards avoiding this, and also making this webservice
call faster.
For now, I'd propose having a hard limit on the number of entries this
webservice can return.
Also, I'd prefer having a webservice to return jobIds (based on the specified
filters), instead of returning completed job info. The jobs/{jobId} webservice
can then be used to pull job info for each job.
The order of results returned can be problematic as well. The webservice
doesn't have an order parameter - and ends up depending on whatever order the
history server returns, which can change in the future.
> JobHistory web services are slower then the UI and can easly overload the JH
> ----------------------------------------------------------------------------
>
> Key: MAPREDUCE-3944
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3944
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 0.23.1, 0.23.2
> Reporter: Robert Joseph Evans
> Assignee: Robert Joseph Evans
> Priority: Blocker
>
> When our first customer started using the Job History web services today the
> History Server ground to a halt. We found 250 Jetty threads stuck on the
> following stack trace.
> {noformat}
> java.lang.Thread.State: BLOCKED (on object monitor)
> at
> org.apache.hadoop.mapreduce.v2.hs.JobHistory.getJob(JobHistory.java:898)
> - waiting to lock <0x00002aaab364ba60> (a
> org.apache.hadoop.mapreduce.v2.hs.JobHistory)
> at
> org.apache.hadoop.mapreduce.v2.hs.webapp.HsWebServices.getJobs(HsWebServices.java:188)
> {noformat}
> HsWebServices.java:188 corresponds to the /mapreduce/jobs service.
> Looking at the code there are a number of optimizations that need to be done
> to improve its performance.
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