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https://issues.apache.org/jira/browse/HADOOP-14236?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15947439#comment-15947439
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Steve Loughran edited comment on HADOOP-14236 at 3/29/17 4:26 PM:
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As mingliang has just pointed out to me, s3a's {{mkdirs()}} doesn't delete mock
parent paths, so
{{mkdir /a}} creates "a/"
{{mkdir /a/b}} creates "a/b/" and leaves "a/"
only in the {{reate(a/b/c.txt)}} will a/ and b/ get deleted
FS contract tests need to verify empty directory create through sequence of
{code}
mkdir a
mkdir a/b
mkdir a/b/c
rename (a, d)
assertIsDir(d/b)
assertIsDir(d/b/c)
{code}
+ maybe also create the dest path using 1+ mkdir call, so it also has mock
parent entries
was (Author: [email protected]):
As mingliang has just pointed out to me, s3a's {{mkdirs()}} doesn't delete mock
parent paths, so
{{mkdir /a}} creates "a/"
{{mkdir /a/b}} creates "a/b/" and leaves "a/"
only in the {{reate(a/b/c.txt)}} will a/ and b/ get deleted
FS contract tests need to verify empty directory create through sequence of
{code}
mkdir a
mkdir a/b
mkdir a/b/c
rename (a, d)
assertIsDir(d/b)
assertIsDir(d/b/c)
{code}
> 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
> Priority: Critical
> Attachments: HADOOP-14236-HADOOP-13345.000.patch,
> HADOOP-14236-HADOOP-13345.001.patch, HADOOP-14236-HADOOP-13345.002.patch
>
>
> 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_.
> UPDATE: modified test case {{ITestS3AFileSystemContract::
> testRenameDirectoryAsExistingDirectory()}} will fail w/o this patch; it
> passes w/ this patch. If the test case makes sense, the proposal follows.
> Existing tests are not complaining about this though. If this is a real bug,
> let’s address it here.
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