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From "Rajesh Balamohan (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HIVE-15129) LLAP : Enhance cache hits for stripe metadata across queries
Date Fri, 04 Nov 2016 11:07:58 GMT

     [ https://issues.apache.org/jira/browse/HIVE-15129?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Rajesh Balamohan updated HIVE-15129:
------------------------------------
    Description: 
When multiple queries are run in LLAP, stripe metadata cache misses were observed even though
enough memory was available. 
https://github.com/apache/hive/blob/master/llap-server/src/java/org/apache/hadoop/hive/llap/io/encoded/OrcEncodedDataReader.java#L655.
Even though data would be found in cache, it wasn't getting used as {{globalnc}} changed from
query to query.  This 
would be lot more beneficial in cloud storage where opening and reading small of data can
be expensive compared to HDFS.

  was:Would be lot more beneficial in cloud storage where opening and reading small of data
can be expensive compared to HDFS.


> LLAP : Enhance cache hits for stripe metadata across queries
> ------------------------------------------------------------
>
>                 Key: HIVE-15129
>                 URL: https://issues.apache.org/jira/browse/HIVE-15129
>             Project: Hive
>          Issue Type: Improvement
>          Components: llap
>            Reporter: Rajesh Balamohan
>            Priority: Minor
>
> When multiple queries are run in LLAP, stripe metadata cache misses were observed even
though enough memory was available. 
> https://github.com/apache/hive/blob/master/llap-server/src/java/org/apache/hadoop/hive/llap/io/encoded/OrcEncodedDataReader.java#L655.
Even though data would be found in cache, it wasn't getting used as {{globalnc}} changed from
query to query.  This 
> would be lot more beneficial in cloud storage where opening and reading small of data
can be expensive compared to HDFS.



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