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https://issues.apache.org/jira/browse/HADOOP-6688?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12856145#action_12856145
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Danny Leshem commented on HADOOP-6688:
--------------------------------------
Tom, this is a classic issue of coding "for the programmer" or "against the
programmer".
What is the expected effect of calling FileSystem.delete(someFile)? A
reasonable answer would be "someFile no longer exists", and the method should
throw an exception only if that expected effect somehow did not happen, meaning
the file is there.
For those unlikely users who care whether the file was actually deleted or
wasn't there to begin with, you can have FileSystem.delete() return a boolean
to convey this information. This is common practice in many file system APIs.
I have no idea as to the root cause of the file not existing. It might be a
similar consistency issue to the one you mentioned - I have not looked into it.
Since fixing FileSystem.delete is rather easy (and the change is very
contained), I think it's a better solution than working around the issue.
> FileSystem.delete(...) implementations should not throw FileNotFoundException
> -----------------------------------------------------------------------------
>
> 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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