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Hadoop, mail # user - MapFiles error "Could not obtain block"


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Re: MapFiles error "Could not obtain block"
Jeff Bean 2010-11-19, 00:14
Hi Kim,

I saw this problem once, turned out the block was getting deleted before it
was read. Check namenode for blk_-7027776556206952935_61338. What's the
story there?

Jeff

On Thu, Nov 18, 2010 at 12:45 PM, Kim Vogt <[EMAIL PROTECTED]> wrote:

> Hi,
>
> I'm using the MapFileOutputFormat to lookup values in MapFiles and keep
> getting "Could not obtain block" errors.  I'm thinking it might be because
> ulimit is not set high enough.  Has anyone else run into this issue?
>
> attempt_201011180019_0005_m_000003_0: Caught exception while getting cached
> files: java.io.IOException: Could not obtain block:
> blk_-7027776556206952935_61338 file=/mydata/part-r-00000/data
> attempt_201011180019_0005_m_000003_0:     at
>
> org.apache.hadoop.hdfs.DFSClient$DFSInputStream.chooseDataNode(DFSClient.java:1976)
> attempt_201011180019_0005_m_000003_0:     at
>
> org.apache.hadoop.hdfs.DFSClient$DFSInputStream.blockSeekTo(DFSClient.java:1783)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.hdfs.DFSClient$DFSInputStream.read(DFSClient.java:1931)
> attempt_201011180019_0005_m_000003_0:     at
> java.io.DataInputStream.readFully(DataInputStream.java:178)
> attempt_201011180019_0005_m_000003_0:     at
> java.io.DataInputStream.readFully(DataInputStream.java:152)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.SequenceFile$Reader.init(SequenceFile.java:1457)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1435)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1424)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.SequenceFile$Reader.<init>(SequenceFile.java:1419)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.MapFile$Reader.createDataFileReader(MapFile.java:302)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.MapFile$Reader.open(MapFile.java:284)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.MapFile$Reader.<init>(MapFile.java:273)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.MapFile$Reader.<init>(MapFile.java:260)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.io.MapFile$Reader.<init>(MapFile.java:253)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:639)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.mapred.MapTask.run(MapTask.java:315)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.mapred.Child$4.run(Child.java:217)
> attempt_201011180019_0005_m_000003_0:     at
> java.security.AccessController.doPrivileged(Native Method)
> attempt_201011180019_0005_m_000003_0:     at
> javax.security.auth.Subject.doAs(Subject.java:396)
> attempt_201011180019_0005_m_000003_0:     at
>
> org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1063)
> attempt_201011180019_0005_m_000003_0:     at
> org.apache.hadoop.mapred.Child.main(Child.java:211)
>
> -Kim
>