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https://issues.apache.org/jira/browse/HDFS-6984?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Colin Patrick McCabe updated HDFS-6984:
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Description:
FileStatus was a Writable in Hadoop 2 and earlier. Originally, we used this to
serialize it and send it over the wire. But in Hadoop 2 and later, we have the
protobuf {{HdfsFileStatusProto}} which serves to serialize this information.
The protobuf form is preferable, since it allows us to add new fields in a
backwards-compatible way. Another issue is that already a lot of subclasses of
FileStatus don't override the Writable methods of the superclass, breaking the
interface contract that read(status.write) should be equal to the original
status.
In Hadoop 3, we should just make FileStatus serialize itself via protobuf so
that we don't have to deal with these issues. It's probably too late to do
this in Hadoop 2, since user code may be relying on the existing FileStatus
serialization there.
was:
FileStatus was a Writable in Hadoop 2 and earlier. Originally, we used this to
serialize it and send it over the wire. But in Hadoop 2 and later, we have the
protobuf {{HdfsFileStatusProto}} which serves to serialize this information.
The protobuf form is preferable, since it allows us to add new fields in a
backwards-compatible way. Another issue is that already a lot of subclasses of
FileStatus don't override the Writable methods of the superclass, breaking the
interface contract that read(status.write) should be equal to the original
status.
In Hadoop 3, we should just make FileStatus no longer a writable so that we
don't have to deal with these issues. It's probably too late to do this in
Hadoop 2, since user code may be relying on the ability to use the Writable
methods on FileStatus objects there.
> In Hadoop 3, make FileStatus serialize itself via protobuf
> ----------------------------------------------------------
>
> Key: HDFS-6984
> URL: https://issues.apache.org/jira/browse/HDFS-6984
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 3.0.0
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Labels: BB2015-05-TBR
> Attachments: HDFS-6984.001.patch, HDFS-6984.002.patch
>
>
> FileStatus was a Writable in Hadoop 2 and earlier. Originally, we used this
> to serialize it and send it over the wire. But in Hadoop 2 and later, we
> have the protobuf {{HdfsFileStatusProto}} which serves to serialize this
> information. The protobuf form is preferable, since it allows us to add new
> fields in a backwards-compatible way. Another issue is that already a lot of
> subclasses of FileStatus don't override the Writable methods of the
> superclass, breaking the interface contract that read(status.write) should be
> equal to the original status.
> In Hadoop 3, we should just make FileStatus serialize itself via protobuf so
> that we don't have to deal with these issues. It's probably too late to do
> this in Hadoop 2, since user code may be relying on the existing FileStatus
> serialization there.
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