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https://issues.apache.org/jira/browse/DRILL-3754?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zelaine Fong reassigned DRILL-3754:
-----------------------------------
Assignee: Chunhui Shi (was: Jinfeng Ni)
Assigning to [~cshi] for code review
> Remove redundancy in run-time generated code for common column references.
> ---------------------------------------------------------------------------
>
> Key: DRILL-3754
> URL: https://issues.apache.org/jira/browse/DRILL-3754
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Codegen
> Affects Versions: 1.1.0
> Reporter: Jinfeng Ni
> Assignee: Chunhui Shi
> Fix For: Future
>
> Attachments:
> 0002-DRILL-3754-Reduce-redundancy-in-run-time-generated-c.patch
>
>
> When a operator (Filter, project) has expression which refer one same field
> multiple times, Drill will initialize a value vector and do value holder
> assignment for each field reference in the run-time generated code. The
> redundancy might impact the expression evaluation, after the compiled code is
> executed over large number of incoming rows.
> This has been seen in recent performance issue reported on the drill user
> list, where the query contains multiple multiple in list filter conditions.
> In this JIRA, we'll remove the redundancy for the common field reference, so
> that only one initialization and assignment happen in the run-time generated
> code.
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