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https://issues.apache.org/jira/browse/HADOOP-1377?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Doug Cutting updated HADOOP-1377:
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Status: Open (was: Patch Available)
1. FsShell.java needs to import java.text.SimpleDateFormat.
2. We should deprecate the FileSystem methods getReplication, getBlockSize,
getLength and isDirectory. And these should no longer be abstract methods, but
should be implemented in terms of getStatus().
3. This issue should implement getStatus() for all FileSystem implementations,
doing more than throwing an exception. These can be implemented to call the
FileSystem getReplication, getBlockSize, isDirectory and getLength
implementations. So only getCreationTime and getModificationTime cannot
trivially be properly implemented. I'm not certain whether in these cases it
is better to throw an exception or return zero.
> Creation time and modification time for hadoop files and directories
> --------------------------------------------------------------------
>
> Key: HADOOP-1377
> URL: https://issues.apache.org/jira/browse/HADOOP-1377
> Project: Hadoop
> Issue Type: New Feature
> Components: dfs
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
> Attachments: CreationModificationTime.html, CreationTime5.patch
>
>
> This issue will document the requirements, design and implementation of
> creation times and modification times of hadoop files and directories.
> My proposal is to have support two additional attributes for each file and
> directory in HDFS. The "creation time" is the time when the file/directory
> was created. It is a 8 byte integer stored in each FSDirectory.INode. The
> "modification time" is the time when the last modification occured to the
> file/directory. It is an 8 byte integer stored in the FSDirectory.INode.
> These two fields are stored in in the FSEdits and FSImage as part of the
> transaction that created the file/directory.
> My current proposal is to not support "access time" for a file/directory. It
> is costly to implement and current applications might not need it.
> In the current implementation, the "modification time" for a file will be
> same as its creation time because HDFS files are currently unmodifiable.
> Setting file attributes (e.g. setting the replication factor) of a file does
> not modify the "modification time" of that file. The "modification time" for
> a directory is either its creation time or the time when the most recent
> file-delete or file-create occured in that directory.
> A new command named "hadoop dfs -lsl" will display the creation time and
> modification time of the files/directories that it lists. The output of the
> existing command "hadoop dfs -ls" will not be affected.
> The ClientProtocol will change because DFSFileInfo will have two additional
> fields: the creation time and modification time of the file that it
> represents. This information can be retrieved by clients thorugh the
> ClientProtocol.getListings() method. The FileSystem public API will have two
> additional methods: getCreationTime and getModificationTime().
> The datanodes are completely transparent to this design and implementation
> and requires no change.
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