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Posted to common-issues@hadoop.apache.org by "Weiwei Yang (JIRA)" <ji...@apache.org> on 2016/03/31 05:28:25 UTC
[jira] [Commented] (HADOOP-11334) Mapreduce Job Failed due to
failure fetching mapper output on the reduce side
[ https://issues.apache.org/jira/browse/HADOOP-11334?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15219268#comment-15219268 ]
Weiwei Yang commented on HADOOP-11334:
--------------------------------------
Agree with Eric, we should get this fixed. At least implement option 2 so it won't fail in this ugly way it does today.
> Mapreduce Job Failed due to failure fetching mapper output on the reduce side
> -----------------------------------------------------------------------------
>
> Key: HADOOP-11334
> URL: https://issues.apache.org/jira/browse/HADOOP-11334
> Project: Hadoop Common
> Issue Type: Bug
> Components: io
> Affects Versions: 2.4.1
> Reporter: Jinghui Wang
> Assignee: Yuanbo Liu (Yuan Bo Liu)
>
> Running terasort with the following options hadoop jar hadoop-mapreduce-examples.jar terasort *-Dio.native.lib.available=false -Dmapreduce.map.output.compress=true -Dmapreduce.map.output.compress.codec=org.apache.hadoop.io.compress.GzipCodec* /tmp/tera-in /tmp/tera-out
> The job failed with the reducer failed to fetch the output from mappers (see the following stacktrace). The problem is that in JIRA MAPREDUCE-1784, it added support to handle null compressors to default to non-compressed output. In this case, when the *io.native.lib.available* is set to false, the compressor will be null. However, the decompressor has a Java implementation, so when the reducer tries to read the mapper output, it uses the decompressor, but the output does not have the Gzip header.
> 2014-11-25 10:39:48,108 WARN [fetcher#9] org.apache.hadoop.mapreduce.task.reduce.Fetcher: Failed to shuffle output of attempt_1416875111322_0005_m_000002_0 from bdvs130:13562
> java.io.IOException: not a gzip file
> at org.apache.hadoop.io.compress.zlib.BuiltInGzipDecompressor.processBasicHeader(BuiltInGzipDecompressor.java:495)
> at org.apache.hadoop.io.compress.zlib.BuiltInGzipDecompressor.executeHeaderState(BuiltInGzipDecompressor.java:256)
> at org.apache.hadoop.io.compress.zlib.BuiltInGzipDecompressor.decompress(BuiltInGzipDecompressor.java:185)
> at org.apache.hadoop.io.compress.DecompressorStream.decompress(DecompressorStream.java:91)
> at org.apache.hadoop.io.compress.DecompressorStream.read(DecompressorStream.java:85)
> at org.apache.hadoop.io.IOUtils.readFully(IOUtils.java:192)
> at org.apache.hadoop.mapreduce.task.reduce.InMemoryMapOutput.shuffle(InMemoryMapOutput.java:97)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyMapOutput(Fetcher.java:434)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.copyFromHost(Fetcher.java:341)
> at org.apache.hadoop.mapreduce.task.reduce.Fetcher.run(Fetcher.java:165)
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