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https://issues.apache.org/jira/browse/HIVE-10302?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Xuefu Zhang updated HIVE-10302:
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Description: Usually there are multiple cores in a Spark executor, and thus
it's possible that multiple map-join tasks can be running in the same executor
(concurrently or sequentially). Currently, each task will load its own copy of
the small tables for map join into memory, ending up with inefficiency.
Ideally, we only load the small tables once and share them among the tasks
running in that executor. (was: If we can cache small tables in executor
memory, we could save some time in loading them from HDFS.)
> Load small tables (for map join) in executor memory only once [Spark Branch]
> ----------------------------------------------------------------------------
>
> Key: HIVE-10302
> URL: https://issues.apache.org/jira/browse/HIVE-10302
> Project: Hive
> Issue Type: Improvement
> Reporter: Jimmy Xiang
> Assignee: Jimmy Xiang
> Fix For: spark-branch
>
> Attachments: HIVE-10302.spark-1.patch
>
>
> Usually there are multiple cores in a Spark executor, and thus it's possible
> that multiple map-join tasks can be running in the same executor
> (concurrently or sequentially). Currently, each task will load its own copy
> of the small tables for map join into memory, ending up with inefficiency.
> Ideally, we only load the small tables once and share them among the tasks
> running in that executor.
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