hadoop-mapreduce-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Joydeep Sen Sarma (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MAPREDUCE-2026) JobTracker.getJobCounters() should not hold JobTracker lock while calling JobInProgress.getCounters()
Date Wed, 13 Oct 2010 14:26:37 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2026?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12920580#action_12920580
] 

Joydeep Sen Sarma commented on MAPREDUCE-2026:
----------------------------------------------

if the client doesn't want updated getCounters - they can reduce the polling interval (for
updating the counters). this can be a change made in the jsp code (if that is generating most
of the calls in your case).
for this reason - we didn't put any caching in the jobtracker. (in our case - most of the
calls come from the hive clients and the poll interval is already configurable for hive).

might be worth following up on a new jira?

> JobTracker.getJobCounters() should not hold JobTracker lock while calling JobInProgress.getCounters()
> -----------------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-2026
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2026
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>            Reporter: Scott Chen
>            Assignee: Joydeep Sen Sarma
>             Fix For: 0.22.0
>
>         Attachments: 2026.1.patch, MAPREDUCE-2026.txt
>
>
> JobTracker.getJobCounter() will lock JobTracker and call JobInProgress.getCounters().
> JobInProgress.getCounters() can be very expensive because it aggregates all the task
counters.
> We found that from the JobTracker jstacks that this method is one of the bottleneck of
the JobTracker performance.
> JobInProgress.getCounters() should be able to be called out side the JobTracker lock
because it already has JobInProgress lock.
> For example, it is used by jobdetails.jsp without a JobTracker lock.

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


Mime
View raw message