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https://issues.apache.org/jira/browse/HDFS-8058?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhe Zhang updated HDFS-8058:
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Attachment: HDFS-8058-HDFS-7285.003.patch
Updated patch based on the original idea.
In general, I think we should use the {{BlockInfo}} abstraction in most cases,
and use specific subclasses when:
# Creating new instances
# Calling striping specific operations (e.g. {{getCellSize}}) and UC specific
ones.
To verify the properties of a {{BlockInfo}} instance we should use {{isXxx}}
interfaces.
This is perhaps the only way to address the multi-inheritance problem for
{{BlockInfo}}. In the future we are likely to have more types of {{BlockInfo}}
that we want to handle specially, like non-striping erasure-coded blocks
(HDFS-8030), and the multi-inheritance relationship will be too complex to
handle via subclassing.
The patch also has 2 changes to ensure a file has all striped or all contiguous
blocks:
# {{isStriped}} checking in {{addBlock}} and {{concatBlocks}}
# Removed public {{setBlocks}} and replaced with {{clearBlocks}}
> Erasure coding: use BlockInfo[] for both striped and contiguous blocks in
> INodeFile
> -----------------------------------------------------------------------------------
>
> Key: HDFS-8058
> URL: https://issues.apache.org/jira/browse/HDFS-8058
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Affects Versions: HDFS-7285
> Reporter: Yi Liu
> Assignee: Yi Liu
> Attachments: HDFS-8058-HDFS-7285.003.patch, HDFS-8058.001.patch,
> HDFS-8058.002.patch
>
>
> This JIRA is to use {{BlockInfo[] blocks}} for both striped and contiguous
> blocks in INodeFile.
> Currently {{FileWithStripedBlocksFeature}} keeps separate list for striped
> blocks, and the methods there duplicate with those in INodeFile, and current
> code need to judge {{isStriped}} then do different things. Also if file is
> striped, the {{blocks}} in INodeFile occupy a reference memory space.
> These are not necessary, and we can use the same {{blocks}} to make code more
> clear.
> I keep {{FileWithStripedBlocksFeature}} as empty for follow use: I will file
> a new JIRA to move {{dataBlockNum}} and {{parityBlockNum}} from
> *BlockInfoStriped* to INodeFile, since ideally they are the same for all
> striped blocks in a file, and store them in block will waste NN memory.
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