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From "Edward Capriolo (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-4963) Support in memory PTF partitions
Date Wed, 21 Aug 2013 17:39:53 GMT

    [ https://issues.apache.org/jira/browse/HIVE-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13746617#comment-13746617
] 

Edward Capriolo commented on HIVE-4963:
---------------------------------------

{quote}
Yes this is much more work to do. More importantly, its not PTF specific either, its in existing
code which Harish has chosen to reuse. I dont think its fair to hold on to this patch for
this. It can be done in a follow-up.
{quote}
Agreed. If extending an existing component that already does it this way, changing both is
out-of-scope.
                
> Support in memory PTF partitions
> --------------------------------
>
>                 Key: HIVE-4963
>                 URL: https://issues.apache.org/jira/browse/HIVE-4963
>             Project: Hive
>          Issue Type: New Feature
>          Components: PTF-Windowing
>            Reporter: Harish Butani
>            Assignee: Harish Butani
>         Attachments: HIVE-4963.D11955.1.patch, HIVE-4963.D12279.1.patch, HIVE-4963.D12279.2.patch,
PTFRowContainer.patch
>
>
> PTF partitions apply the defensive mode of assuming that partitions will not fit in memory.
Because of this there is a significant deserialization overhead when accessing elements. 
> Allow the user to specify that there is enough memory to hold partitions through a 'hive.ptf.partition.fits.in.mem'
option.  
> Savings depends on partition size and in case of windowing the number of UDAFs and the
window ranges. For eg for the following (admittedly extreme) case the PTFOperator exec times
went from 39 secs to 8 secs.
>  
> {noformat}
> select t, s, i, b, f, d,
> min(t) over(partition by 1 rows between unbounded preceding and current row), 
> min(s) over(partition by 1 rows between unbounded preceding and current row), 
> min(i) over(partition by 1 rows between unbounded preceding and current row), 
> min(b) over(partition by 1 rows between unbounded preceding and current row) 
> from over10k
> {noformat}

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