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https://issues.apache.org/jira/browse/MAPREDUCE-6473?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14907012#comment-14907012
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Jason Lowe commented on MAPREDUCE-6473:
---------------------------------------
The problem is this step:
bq. T1 hasn't finished populating the list but has initialized it
and the fix is to use a local variable while the list is being initialized then
set providerList to the completely built list when we're done.
> Job submission can take a long time during Cluster initialization
> -----------------------------------------------------------------
>
> Key: MAPREDUCE-6473
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-6473
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: performance
> Reporter: Kuhu Shukla
> Assignee: Kuhu Shukla
> Attachments: 99%ile.png, MAPREDUCE-6473-PerfTest.txt,
> MAPREDUCE-6473-v1.patch, MAPREDUCE-6473-v2.patch, MAPREDUCE-6473-v3.patch,
> MAPREDUCE-6473-v4.patch, MAPREDUCE-6473-v5.patch, avgtime.png
>
>
> During initialization in Cluster.java, the framework provider classes are
> loaded inside a sync block which can considerably increase job submission
> time when the number of submissions are high. The motive is to reduce time
> spent in this sync block safely to improve performance.
> {noformat}
> synchronized (frameworkLoader) {
> for (ClientProtocolProvider provider : frameworkLoader) {
> LOG.debug("Trying ClientProtocolProvider : "
> + provider.getClass().getName());
> {noformat}
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