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Posted to issues@hive.apache.org by "Owen O'Malley (JIRA)" <ji...@apache.org> on 2017/07/26 00:04:10 UTC
[jira] [Closed] (HIVE-15129) LLAP : Enhance cache hits for stripe
metadata across queries
[ https://issues.apache.org/jira/browse/HIVE-15129?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Owen O'Malley closed HIVE-15129.
--------------------------------
> 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
> Affects Versions: 2.2.0
> Reporter: Rajesh Balamohan
> Assignee: Rajesh Balamohan
> Priority: Minor
> Fix For: 2.2.0
>
> Attachments: HIVE-15129.1.patch, HIVE-15129.2.patch, HIVE-15129.3.patch
>
>
> 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 in cases when data was found in cache, it wasn't getting used as {{globalnc}} changed from query to query. Creating a superset of existing indexes with {{globalInc}} would be helpful.
> 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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