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Posted to issues@arrow.apache.org by "Micah Kornfield (JIRA)" <ji...@apache.org> on 2019/06/20 06:45:00 UTC

[jira] [Resolved] (ARROW-5639) [Java] Remove floating point computation from getOffsetBufferValueCapacity

     [ https://issues.apache.org/jira/browse/ARROW-5639?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Micah Kornfield resolved ARROW-5639.
------------------------------------
       Resolution: Fixed
    Fix Version/s: 0.14.0

Issue resolved by pull request 4602
[https://github.com/apache/arrow/pull/4602]

> [Java] Remove floating point computation from getOffsetBufferValueCapacity
> --------------------------------------------------------------------------
>
>                 Key: ARROW-5639
>                 URL: https://issues.apache.org/jira/browse/ARROW-5639
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: Java
>            Reporter: Liya Fan
>            Assignee: Liya Fan
>            Priority: Trivial
>              Labels: pull-request-available
>             Fix For: 0.14.0
>
>         Attachments: image-2019-06-18-20-30-17-826.png
>
>          Time Spent: 1.5h
>  Remaining Estimate: 0h
>
> Some getOffsetBufferValueCapacity methods uses floating point computation to calculate the capacity, which is not necessary.
> (int) ((offsetBuffer.capacity() * 1.0) / OFFSET_WIDTH);
> It is interesting to note that JIT cannot optimize away the floating point computations:
>  !image-2019-06-18-20-30-17-826.png! 
> So this has performance penalty:
> Before:
> VariableWidthVectorBenchmarks.getValueCapacity  avgt    5  6.570 ± 0.004  ns/op
> After:
> VariableWidthVectorBenchmarks.getValueCapacity  avgt    5  5.787 ± 0.575  ns/op



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