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https://issues.apache.org/jira/browse/HIVE-15520?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15802718#comment-15802718
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Aihua Xu commented on HIVE-15520:
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patch-1: Instead of calculating the function value by aggregating all the rows
in the window for each row, we calculate the new function value based on the
previous row. Assume the window of previous row is [p1, p2] and the current is
[p1', p2'], the new_sum = sum + [p2, p2'] - [p1, p1'].
> Improve the performance for Range based window
> ----------------------------------------------
>
> Key: HIVE-15520
> URL: https://issues.apache.org/jira/browse/HIVE-15520
> Project: Hive
> Issue Type: Sub-task
> Components: PTF-Windowing
> Reporter: Aihua Xu
> Assignee: Aihua Xu
> Attachments: HIVE-15520.1.patch
>
>
> Currently streaming process is not supported for range based windowing. Thus
> sum( x ) over (partition by y order by z) is O(n^2) running time.
> Investigate the possibility of streaming support.
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