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https://issues.apache.org/jira/browse/HDFS-11644?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15968113#comment-15968113
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stack commented on HDFS-11644:
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bq. "The current behavior of throwing an exception is safer."
... but changes precedent?
Semantics in general are messy here around sync, et al. It is a reflection of
he torturous journey taken by sync/flush/hflush/hsync in HDFS.
The blessed [[email protected]] tried writing a spec for DFS and got far on
the read-side. Helps. Write-side is to do. I like Steves' comment that rather
than "....probe for interface, cast, query, maintain.." at each point at which
we encounter a feature, rather, there'd be an upfront query that could be run
before engaging w/ the fs implementation (though how does this work if tiering
changes the underlying storage on us at runtime?).
Meantime, having DFSStripedOutputStream throw an exception breaking all that
run on top (with no means of querying whether support or not) seems disruptive.
> DFSStripedOutputStream should not implement Syncable
> ----------------------------------------------------
>
> Key: HDFS-11644
> URL: https://issues.apache.org/jira/browse/HDFS-11644
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: erasure-coding
> Affects Versions: 3.0.0-alpha1
> Reporter: Andrew Wang
> Assignee: Manoj Govindassamy
> Labels: hdfs-ec-3.0-must-do
>
> FSDataOutputStream#hsync checks if a stream implements Syncable, and if so,
> calls hsync. Otherwise, it just calls flush. This is used, for instance, by
> YARN's FileSystemTimelineWriter.
> DFSStripedOutputStream extends DFSOutputStream, which implements Syncable.
> However, DFSStripedOS throws a runtime exception when the Syncable methods
> are called.
> We should refactor the inheritance structure so DFSStripedOS does not
> implement Syncable.
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