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https://issues.apache.org/jira/browse/HIVE-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13746554#comment-13746554
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Ashutosh Chauhan commented on HIVE-4963:
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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.
> 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
> 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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