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From "Ahmed Fathalla (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CHUKWA-4) Collectors don't finish writing .done datasink from last .chukwa datasink when stopped using bin/stop-collectors
Date Sat, 03 Apr 2010 19:45:28 GMT

    [ https://issues.apache.org/jira/browse/CHUKWA-4?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12853188#action_12853188
] 

Ahmed Fathalla commented on CHUKWA-4:
-------------------------------------

I am working on a helper class that could be called before the moveFile method in LocalToRemoteHDFSMover,
the purpose of this helper would be to copy the contents of the (possibly corrupt) .chukwa
file into a valid sink file. Here is the class I created

public class CopySequenceFile {
  static Logger log = Logger.getLogger(LocalWriter.class);
  private static SequenceFile.Writer seqFileWriter = null;
  private static SequenceFile.Reader seqFileReader = null; 
  private static FSDataOutputStream newOutputStr = null;
  
  public static void main(String args[]){
		
	}
	
  public static void createValidSequenceFile(Configuration conf, String originalFileDir, String
originalFileName,FileSystem localFs){
    try{
	  String originalCompleteDir= originalFileDir + originalFileName;
	  Path originalPath= new Path (originalCompleteDir);
	  int extensionIndex= originalFileName.indexOf(".chukwa",0);
	  String newFileName=originalFileName.substring(0, extensionIndex)+".recover";
	  String newCompleteDir= originalFileDir+ newFileName;
	  Path newPath= new Path (newCompleteDir);
	  
	  newOutputStr = localFs.create(newPath);
      seqFileWriter = SequenceFile.createWriter(conf, newOutputStr,
        ChukwaArchiveKey.class, ChunkImpl.class,
        SequenceFile.CompressionType.NONE, null);
      seqFileReader = new SequenceFile.Reader (localFs, originalPath, conf);
        
      System.out.println("key class name is " + seqFileReader.getKeyClassName());
      System.out.println("value class name is " + seqFileReader.getValueClassName());
      ChukwaArchiveKey key = new ChukwaArchiveKey();
      ChunkImpl evt = ChunkImpl.getBlankChunk();
        
       while (seqFileReader.next(key, evt)){
         seqFileWriter.append(key, evt);
        }
       //Remove original .chukwa file
       localFs.delete(originalPath,false);
       //Rename the file from .recover back to .chukwa 
       localFs.rename(originalPath, newPath);
	   seqFileReader.close();
	   seqFileWriter.close();
	   newOutputStr.close();
	}
 
	catch(Exception e){
		 log.warn("Error while copying .chukwa file to valid sink file",e);		 
		 e.printStackTrace();
	}	
  }
}


However when the createValidSequenceFile method is called a ChecksumException is thrown when
seqFileReader.next(key, evt) is being executed. (BTW this is the same exception that was causing
moveFile to fail in LocalToRemoteHDFSMover, it seems to happen when the reader reaches the
corrupt chunk).

My question is : Is there a way to identify that the chunk being read is corrupt and if so,
not to read it, and close the sink file being copied to? 

> Collectors don't finish writing .done datasink from last .chukwa datasink when stopped
using bin/stop-collectors
> ----------------------------------------------------------------------------------------------------------------
>
>                 Key: CHUKWA-4
>                 URL: https://issues.apache.org/jira/browse/CHUKWA-4
>             Project: Hadoop Chukwa
>          Issue Type: Bug
>          Components: data collection
>         Environment: I am running on our local cluster. This is a linux machine that
I also run Hadoop cluster from.
>            Reporter: Andy Konwinski
>            Priority: Minor
>
> When I use start-collectors, it creates the datasink as expected, writes to it as per
normal, i.e. writes to the .chukwa file, and roll overs work fine when it renames the .chukwa
file to .done. However, when I use bin/stop-collectors to shut down the running collector
it leaves a .chukwa file in the HDFS file system. Not sure if this is a valid sink or not,
but I think that the collector should gracefully clean up the datasink and rename it .done
before exiting.

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