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https://issues.apache.org/jira/browse/HDFS-9027?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mingliang Liu updated HDFS-9027:
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Status: Open (was: Patch Available)
> Refactor o.a.h.hdfs.DataStreamer#isLazyPersist() method
> -------------------------------------------------------
>
> Key: HDFS-9027
> URL: https://issues.apache.org/jira/browse/HDFS-9027
> Project: Hadoop HDFS
> Issue Type: Task
> Reporter: Mingliang Liu
> Assignee: Mingliang Liu
> Attachments: HDFS-9027.000.patch
>
>
> In method {{isLazyPersist()}}, the {{org.apache.hadoop.hdfs.DataStreamer}}
> class checks whether the HDFS file is lazy persist. It does two things:
> 1. Create a class-wide _static_ {{BlockStoragePolicySuite}} object, which
> builds an array of {{BlockStoragePolicy}} internally
> 2. Get a block storage policy object from the {{blockStoragePolicySuite}} by
> policy name {{HdfsConstants.MEMORY_STORAGE_POLICY_NAME}}
> This has two side effects:
> 1. Takes time to iterate the pre-built block storage policy array in order to
> find the _same_ policy every time whose id matters only (as we need to
> compare the file status policy id with lazy persist policy id)
> 2. {{DataStreamer}} class imports {{BlockStoragePolicySuite}}. The former
> should be moved to {{hadoop-hdfs-client}} module, while the latter can stay
> in {{hadoop-hdfs}} module.
> Actually, we have the block storage policy IDs, which can be used to compare
> with HDFS file status' policy id, as following:
> {code}
> static boolean isLazyPersist(HdfsFileStatus stat) {
> return stat.getStoragePolicy() == HdfsConstants.MEMORY_STORAGE_POLICY_ID;
> }
> {code}
> This way, we only need to move the block storage policies' IDs from
> {{HdfsServerConstant}} ({{hadoop-hdfs}} module) to {{HdfsConstants}}
> ({{hadoop-hdfs-client}} module).
> Another reason we should move those block storage policy IDs is that the
> block storage policy names were moved to {{HdfsConstants}} already.
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