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https://issues.apache.org/jira/browse/HDFS-8499?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14640856#comment-14640856
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Zhe Zhang commented on HDFS-8499:
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[~szetszwo]: As mentioned above I'm open to reworking the {{BlockInfo}}
structure to resolve the discrepancy and unblock EC branch rebasing.
In the reworked structure, is your main requirement among the following? I
summarized from the comments. Apologies if I missed anything.
* Being able to cast (and {{instanceof}}) between {{BIContiguous}} /
{{BIContiguousUC}} and {{BIStriped}} / {{BIStripedUC}}
* Sharing code between {{BIContiguous}} / {{BIContiguousUC}} and {{BIStriped}}
/ {{BIStripedUC}}
* Flexibility to implement the two UC classes differently. (BTW, how about
{{BIContiguous}} and {{BIStriped}}? Do you think we should maintain the
flexibility for completely different implementations?).
I'm more concerned about other NN modules relying on type reflections and
casting in this multi-inheritance scenario (first item on the above list). So
I'm OK if you'd like to change to design [#2 |
https://issues.apache.org/jira/browse/HDFS-8499?focusedCommentId=14632040&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14632040]
as an intermediate solution.
If we do that, I still prefer to refactor NN code to replace
{{BlockInfoStriped}} type casting with explicit {{isStriped()}} checks and move
some getters up to {{BlockInfo}} level.
> Refactor BlockInfo class hierarchy with static helper class
> -----------------------------------------------------------
>
> Key: HDFS-8499
> URL: https://issues.apache.org/jira/browse/HDFS-8499
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Affects Versions: 2.7.0
> Reporter: Zhe Zhang
> Assignee: Zhe Zhang
> Fix For: 2.8.0
>
> Attachments: HDFS-8499.00.patch, HDFS-8499.01.patch,
> HDFS-8499.02.patch, HDFS-8499.03.patch, HDFS-8499.04.patch,
> HDFS-8499.05.patch, HDFS-8499.06.patch, HDFS-8499.07.patch,
> HDFS-8499.UCFeature.patch, HDFS-bistriped.patch
>
>
> In HDFS-7285 branch, the {{BlockInfoUnderConstruction}} interface provides a
> common abstraction for striped and contiguous UC blocks. This JIRA aims to
> merge it to trunk.
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