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Posted to mapreduce-issues@hadoop.apache.org by "Jason Lowe (JIRA)" <ji...@apache.org> on 2013/05/15 15:53:15 UTC
[jira] [Commented] (MAPREDUCE-5251) Reducer should not implicate
map attempt if it has insufficient space to fetch map output
[ https://issues.apache.org/jira/browse/MAPREDUCE-5251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13658366#comment-13658366 ]
Jason Lowe commented on MAPREDUCE-5251:
---------------------------------------
Sample exception from a reducer when this occurs:
{noformat}
2013-05-14 01:23:14,382 INFO [fetcher#4]
org.apache.hadoop.mapreduce.task.reduce.Fetcher: fetcher#4 failed to read map headerattempt_1368206650998_32139_m_000258_0 decomp: 3083285359, 324928373
org.apache.hadoop.util.DiskChecker$DiskErrorException: Could not find any valid local directory for output/attempt_1368206650998_32139_r_001028_0/map_258.out
at org.apache.hadoop.fs.LocalDirAllocator$AllocatorPerContext.getLocalPathForWrite(LocalDirAllocator.java:398)
at org.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:150)
at org.apache.hadoop.fs.LocalDirAllocator.getLocalPathForWrite(LocalDirAllocator.java:131)
at org.apache.hadoop.mapred.YarnOutputFiles.getInputFileForWrite(YarnOutputFiles.java:213)
at org.apache.hadoop.mapreduce.task.reduce.MapOutput.<init>(MapOutput.java:80)
at org.apache.hadoop.mapreduce.task.reduce.MergeManager.reserve(MergeManager.java:258)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyMapOutput(Fetcher.java:341)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:276)
at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:156)
2013-05-14 01:23:14,382 WARN [fetcher#4] org.apache.hadoop.mapreduce.task.reduce.Fetcher: copyMapOutput failed for tasks [attempt_1368206650998_32139_m_000258_0]
{noformat}
> Reducer should not implicate map attempt if it has insufficient space to fetch map output
> -----------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-5251
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-5251
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Affects Versions: 0.23.7, 2.0.4-alpha
> Reporter: Jason Lowe
>
> A job can fail if a reducer happens to run on a node with insufficient space to hold a map attempt's output. The reducer keeps reporting the map attempt as bad, and if the map attempt ends up being re-launched too many times before the reducer decides maybe it is the real problem the job can fail.
> In that scenario it would be better to re-launch the reduce attempt and hopefully it will run on another node that has sufficient space to complete the shuffle. Reporting the map attempt is bad and relaunching the map task doesn't change the fact that the reducer can't hold the output.
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