[jira] [Created] (HADOOP-14236) S3Guard: S3AFileSystem::rename() should move non-listed sub-directory entries in metadata store

["Mingliang Liu (JIRA)" <ji...@apache.org>]

Mingliang Liu created HADOOP-14236:
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             Summary: S3Guard: S3AFileSystem::rename() should move non-listed sub-directory entries in metadata store
                 Key: HADOOP-14236
                 URL: https://issues.apache.org/jira/browse/HADOOP-14236
             Project: Hadoop Common
          Issue Type: Sub-task
          Components: fs/s3
            Reporter: Mingliang Liu
            Assignee: Mingliang Liu


After running integration test {{ITestS3AFileSystemContract}}, I found the following items are not cleaned up in DynamoDB:
{code}
parent=/mliu-s3guard/user/mliu/s3afilesystemcontract/testRenameDirectoryAsExisting/dir, child=subdir
parent=/mliu-s3guard/user/mliu/s3afilesystemcontract/testRenameDirectoryAsExistingNew/newdir/subdir, child=file2
{code}
At first I thought it’s similar to [HADOOP-14226] or [HADOOP-14227], and we need to be careful when cleaning up test data.

Then I found it’s a bug in the code of integrating S3Guard with S3AFileSystem: for rename we miss sub-directory items to put (dest) and delete (src). The reason is that in S3A, we delete those fake directory objects if they are not necessary, e.g. non-empty. So when we list the objects to rename, the object summaries will only return _file_ objects. This has two consequences after rename:
#  there will be left items for src path in metadata store - left-overs will confuse {{get(Path)}} which should return null
# we are not persisting the whole subtree for dest path to metadata store - this will break the DynamoDBMetadataStore invariant: _if a path exists, all its ancestors will also exist in the table_.

Existing tests are not complaining about this though. If this is a real bug, let’s address it here.



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