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https://issues.apache.org/jira/browse/HADOOP-2790?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12574087#action_12574087
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Devaraj Das commented on HADOOP-2790:
-------------------------------------
Owen, could you please submit one patch for 0.16 branch. This patch doesn't
apply cleanly there.
> TaskInProgress.hasSpeculativeTask is very inefficient
> -----------------------------------------------------
>
> Key: HADOOP-2790
> URL: https://issues.apache.org/jira/browse/HADOOP-2790
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Owen O'Malley
> Assignee: Owen O'Malley
> Fix For: 0.16.1
>
> Attachments: 2790-2.patch, 2790.patch
>
>
> Each call to JobInProgress.findNewTask can call
> TaskInProgress.hasSpeculativeTask once per a task. Each call to
> hasSpeculativeTask calls System.getCurrentTimeMillis, which can result in
> hundreds of thousands of calls to getCurrentTimeMillis. Additionally, it
> calls TaskInProgress.isOnlyCommitPending, which calls .values() on the map
> from task id to host name and iterates through them to see if any of the
> tasks are in commit pending. It would be better to have a commit pending
> boolean flag in the TaskInProgress. It also looks like there are other
> opportunities here, but those jumped out at me. We should also look at this
> method in the profiler.
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