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https://issues.apache.org/jira/browse/HDFS-12681?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chris Douglas updated HDFS-12681:
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Attachment: HDFS-12681.11.patch
Attaching WIP patch.
This restores the types, but it also preserves a common {{HdfsFileStatus}} API
(to avoid changing internal references excessively, and making the patch
un-reviewable). It is now an interface that is a superset of {{FileStatus}}
(will add a unit test for this).
In v11, {{HdfsNamedFileStatus}} is a subtype of {{FileStatus}} while
{{HdfsLocatedFileStatus}} is a subtype of {{LocatedFileStatus}}. Anything
user-facing already copied a subset of fields from these types, so their
previous relationship to one another is irrelevant to compatibility (i.e., the
fact that {{HdfsLocatedFileStatus}} is no longer a subtype of
{{HdfsFileStatus}} doesn't matter to user code).
While v10 imposed some changes since the types were not distinct, this only
resolves a naming collision, creating {{getBlockLocations}} and
{{getLocatedBlocks}}. It should not be an incompatible change.
There are two other ways this could be solved.
# Lazily populate block locations by keeping a reference to the {{FileSystem}}.
This could not only interfere with GC, but untangling how that would work with
the {{FileSystem}} cache seems like an unnecessary exercise.
# For HDFS-7878, if {{FileStatus}} (and not {{PathHandle}}) was the token, then
the conversion to the user-facing type could preserve metadata in the opaque
blob. This JIRA is required because {{LocatedFileStatus}} contains only the
fields of the base class.
> Fold HdfsLocatedFileStatus into HdfsFileStatus
> ----------------------------------------------
>
> Key: HDFS-12681
> URL: https://issues.apache.org/jira/browse/HDFS-12681
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Attachments: HDFS-12681.00.patch, HDFS-12681.01.patch,
> HDFS-12681.02.patch, HDFS-12681.03.patch, HDFS-12681.04.patch,
> HDFS-12681.05.patch, HDFS-12681.06.patch, HDFS-12681.07.patch,
> HDFS-12681.08.patch, HDFS-12681.09.patch, HDFS-12681.10.patch,
> HDFS-12681.11.patch
>
>
> {{HdfsLocatedFileStatus}} is a subtype of {{HdfsFileStatus}}, but not of
> {{LocatedFileStatus}}. Conversion requires copying common fields and shedding
> unknown data. It would be cleaner and sufficient for {{HdfsFileStatus}} to
> extend {{LocatedFileStatus}}.
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