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https://issues.apache.org/jira/browse/HIVE-5762?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13839195#comment-13839195
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Eric Hanson commented on HIVE-5762:
-----------------------------------
For p, s of 18 or less, a single long can be used. Of course, optimizing for
this would need special-case code. With fixed-point arithmetic, this allows
re-use of the existing code that operates on LongColumnVector to do comparisons
and arithmetic.
> Implement vectorized support for the DECIMAL data type
> ------------------------------------------------------
>
> Key: HIVE-5762
> URL: https://issues.apache.org/jira/browse/HIVE-5762
> Project: Hive
> Issue Type: Sub-task
> Reporter: Eric Hanson
>
> Add support to allow queries referencing DECIMAL columns and expression
> results to run efficiently in vectorized mode. Include unit tests and
> end-to-end tests.
> Before starting or at least going very far, please write design specification
> (a new section for the design spec attached to HIVE-4160) for how support for
> the different DECIMAL types should work in vectorized mode, and the roadmap,
> and have it reviewed.
> It may be feasible to re-use LongColumnVector and related VectorExpression
> classes for fixed-point decimal in certain data ranges. That should be at
> least considered to get faster performance and save code. For unlimited
> precision DECIMAL, a new column vector subtype may be needed, or a
> BytesColumnVector could be re-used.
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