[jira] Created: (HADOOP-6688) FileSystem.delete(...) implementations should not throw FileNotFoundException

["Danny Leshem (JIRA)" <ji...@apache.org>]

FileSystem.delete(...) implementations should not throw FileNotFoundException
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                 Key: HADOOP-6688
                 URL: https://issues.apache.org/jira/browse/HADOOP-6688
             Project: Hadoop Common
          Issue Type: Bug
          Components: fs, fs/s3
    Affects Versions: 0.20.2
         Environment: Amazon EC2/S3
            Reporter: Danny Leshem
            Priority: Blocker
             Fix For: 0.20.3, 0.21.0, 0.22.0


S3FileSystem.delete(Path path, boolean recursive) may fail and throw a FileNotFoundException if a directory is being deleted while at the same time some of its files are deleted in the background.

This is definitely not the expected behavior of a delete method. If one of the to-be-deleted files is found missing, the method should not fail and simply continue. This is true for the general contract of FileSystem.delete, and also for its various implementations: RawLocalFileSystem (and specifically FileUtil.fullyDelete) exhibits the same problem.

The fix is to silently catch and ignore FileNotFoundExceptions in delete loops. This can very easily be unit-tested, at least for RawLocalFileSystem.


The reason this issue bothers me is that the cleanup part of a long (Mahout) MR job inconsistently fails for me, and I think this is the root problem. The log shows:
{code}
java.io.FileNotFoundException: s3://S3-BUCKET/tmp/0008E25BF7554CA9/2521362836721872/DistributedMatrix.times.outputVector/_temporary/_attempt_201004061215_0092_r_000002_0/part-00002: No such file or directory.
	at org.apache.hadoop.fs.s3.S3FileSystem.getFileStatus(S3FileSystem.java:334)
	at org.apache.hadoop.fs.s3.S3FileSystem.listStatus(S3FileSystem.java:193)
	at org.apache.hadoop.fs.s3.S3FileSystem.delete(S3FileSystem.java:303)
	at org.apache.hadoop.fs.s3.S3FileSystem.delete(S3FileSystem.java:312)
	at org.apache.hadoop.mapred.FileOutputCommitter.cleanupJob(FileOutputCommitter.java:64)
	at org.apache.hadoop.mapred.OutputCommitter.cleanupJob(OutputCommitter.java:135)
	at org.apache.hadoop.mapred.Task.runJobCleanupTask(Task.java:826)
	at org.apache.hadoop.mapred.MapTask.run(MapTask.java:292)
	at org.apache.hadoop.mapred.Child.main(Child.java:170)
{code}
(similar errors are displayed for ReduceTask.run)

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