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From "liyunzhang_intel (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-17486) Enable SharedWorkOptimizer in tez on HOS
Date Thu, 28 Sep 2017 02:18:00 GMT

     [ https://issues.apache.org/jira/browse/HIVE-17486?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

liyunzhang_intel updated HIVE-17486:
------------------------------------
    Description: 
in HIVE-16602, Implement shared scans with Tez.

Given a query plan, the goal is to identify scans on input tables that can be merged so the
data is read only once. Optimization will be carried out at the physical level.  In Hive on
Spark, it caches the result of spark work if the spark work is used by more than 1 child spark
work. After sharedWorkOptimizer is enabled in physical plan in HoS, the identical table scans
are merged to 1 table scan. This result of table scan will be used by more 1 child spark work.
Thus we need not do the same computation because of cache mechanism.

  was:
in HIVE-16602, Implement shared scans with Tez.

Given a query plan, the goal is to identify scans on input tables that can be merged so the
data is read only once. Optimization will be carried out at the physical level.  In Hive on
Spark, it caches the result ofsSpark work if the spark work is used by more than 1 child spark
work. After sharedWorkOptimizer is enabled in physical plan in HoS, the identical table scans
are merged to 1 table scan. This result of table scan will be used by more 1 child spark work.
Thus we need not do the same computation because of cache mechanism.


> Enable SharedWorkOptimizer in tez on HOS
> ----------------------------------------
>
>                 Key: HIVE-17486
>                 URL: https://issues.apache.org/jira/browse/HIVE-17486
>             Project: Hive
>          Issue Type: Bug
>            Reporter: liyunzhang_intel
>            Assignee: liyunzhang_intel
>
> in HIVE-16602, Implement shared scans with Tez.
> Given a query plan, the goal is to identify scans on input tables that can be merged
so the data is read only once. Optimization will be carried out at the physical level.  In
Hive on Spark, it caches the result of spark work if the spark work is used by more than 1
child spark work. After sharedWorkOptimizer is enabled in physical plan in HoS, the identical
table scans are merged to 1 table scan. This result of table scan will be used by more 1 child
spark work. Thus we need not do the same computation because of cache mechanism.



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