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Posted to mapreduce-dev@hadoop.apache.org by "ZhuGuanyin (JIRA)" <ji...@apache.org> on 2010/05/27 08:25:38 UTC

[jira] Created: (MAPREDUCE-1821) IFile.Reader should check whether data crc has checked before it stop reading.

IFile.Reader should check whether data crc has checked before it stop reading.
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                 Key: MAPREDUCE-1821
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1821
             Project: Hadoop Map/Reduce
          Issue Type: Bug
          Components: task
            Reporter: ZhuGuanyin
            Assignee: ZhuGuanyin


Currently IFile data has crc checked in IFileInputStream (doRead method), 
Normally the IFile would end with 2 bytes of -1, which means EOF_MARKER for keylength and valuelength, and then with 4 bytes crc checksum;
IFileInputStream  checksumIn would check crc before IFile.Reader get EOF_MARKER, 
IFile.Reader would stop reading when positionToNextRecord() read keylength EOF_MARKER(-1),and valuelength  EOF_MARKER(-1);

But if something error happened(IFile corrupted), if the IFileReader read -1, -1 not at end of the IFile, the data may not checked! 
Then Reader thought it had got all data and close reader......the task may fake success without any WARNing.

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