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https://issues.apache.org/jira/browse/HADOOP-5744?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12710530#action_12710530
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Jim Kellerman commented on HADOOP-5744:
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> Hairong Kuang added a comment - 18/May/09 03:53 PM
> Note that the current implementation in 0.20 does not provide the second
> guarantee described above.
> A byte saw by a reader become invisible when the replica it read from fails.
> Even when the replica that
> a reader is reading from is alive, the recovery of an error caused by another
> replica in the pipeline may
> remove a byte saw by a reader temporary from dfs but recover the byte later.
> A removed byte may never
> get recovered if the writer dies or the writer does not have this byte any
> more.
Yes, this is what HADOOP-4379 is trying to address with Doug Cutting's comment:
> Doug Cutting added a comment - 26/Jan/09 11:20 AM
>
>I think it would be better to add a SequenceFile.Writer method that flushes
>and calls
> FSDataOutputStream.sync. The problem is that SequenceFile.Writer#sync() should
> probably be called flush(), not sync(), but that'd be hard to change. So
> perhaps we
> should add a SequenceFile.Writer#syncFs() method?
> Revisit append
> --------------
>
> Key: HADOOP-5744
> URL: https://issues.apache.org/jira/browse/HADOOP-5744
> Project: Hadoop Core
> Issue Type: Improvement
> Components: dfs
> Affects Versions: 0.20.0
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.21.0
>
> Attachments: AppendSpec.pdf
>
>
> HADOOP-1700 and related issues have put a lot of efforts to provide the first
> implementation of append. However, append is such a complex feature. It turns
> out that there are issues that were initially seemed trivial but needs a
> careful design. This jira revisits append, aiming for a design and
> implementation supporting a semantics that are acceptable to its users.
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