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https://issues.apache.org/jira/browse/HADOOP-5744?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12710524#action_12710524
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Hairong Kuang commented on HADOOP-5744:
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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.
> 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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