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https://issues.apache.org/jira/browse/HIVE-24171?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Aihua Xu reassigned HIVE-24171:
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> Support HDFS reads from observer NameNodes
> ------------------------------------------
>
> Key: HIVE-24171
> URL: https://issues.apache.org/jira/browse/HIVE-24171
> Project: Hive
> Issue Type: New Feature
> Components: Hive
> Affects Versions: 3.0.0
> Reporter: Aihua Xu
> Assignee: Aihua Xu
> Priority: Major
>
> HDFS-12943 introduces the consistent reads from observer NameNodes which can
> boost the read performance and reduces the overloads on active NameNodes.
> To take advantage of this feature, the clients are required to make a msync()
> call after writing the files or before reading the files since observer
> NameNodes could have the stale data for a small window.
> Hive needs to make msync() call to HDFS in some places, e.g., 1) after
> generating the plan files - map.xml and reduce.xml so they can get used later
> by executors; 2) after the intermediate files are generated so they can get
> used by later stages or HS2.
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