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From "Ashutosh Chauhan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-12236) LLAP: Prevent metadata queries from thrashing LLAP cache
Date Tue, 01 Dec 2015 21:10:11 GMT

    [ https://issues.apache.org/jira/browse/HIVE-12236?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15034577#comment-15034577
] 

Ashutosh Chauhan commented on HIVE-12236:
-----------------------------------------

I dont understand either the problem or proposed patch. Queries like {{select *}} don't launch
job anyway, which apparently [~gopalv] is trying to optimize for. Patch AFAICT tries to extend
optimization for {{select col_list }} queries for which select expressions are deemed inexpensive,
which [~hagleitn] seems to suggest is not safe to do. Totally at loss here : ) Suggestions?

> LLAP: Prevent metadata queries from thrashing LLAP cache
> --------------------------------------------------------
>
>                 Key: HIVE-12236
>                 URL: https://issues.apache.org/jira/browse/HIVE-12236
>             Project: Hive
>          Issue Type: Improvement
>          Components: Physical Optimizer
>    Affects Versions: 1.3.0, 2.0.0
>            Reporter: Gopal V
>            Assignee: Gopal V
>         Attachments: HIVE-12236.WIP.patch
>
>
> Currently, metadata queries fired by BI tools tend to thrash LLAP's cache.
> Bypass the cache and process metadata queries directly from HiveServer2



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