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https://issues.apache.org/jira/browse/ARROW-3051?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16580379#comment-16580379
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Dimitri Vorona edited comment on ARROW-3051 at 8/15/18 7:51 AM:
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In that case copy-elision won't work even with the change
[http://cpp.sh/3x25h] . Even worse: while using const reference with temporary
gives a correct behaviour, it disables RVO, since it isn't specified to work on
references (see returnNoisy[2-4]).
EDIT: OTOH, if we return a new Status::OK() in the end of the function, which
is common, RVO won't work anyway, and we save ourselves a copy in the most
common case (i.e. when status is ok).
OK Status copy being virtually free, I doubt we could produce any numbers
showing the difference, but I can't think of any reasonable example, were it
could make things worse.
was (Author: alendit):
In that case copy-elision won't work even with the change
[http://cpp.sh/3x25h] . Even worse: while using const reference with temporary
gives a correct behaviour, it disables RVO, since it isn't specified to work on
references (see returnNoisy[2-4]).
EDIT: OTOH, if we return a new Status::OK() in the end of the function, which
is common, RVO won't work anyway, and we save ourselves a copy in the most
common case (i.e. when status is ok).
OK Status copy being virtually free, I doubt we could produce any numbers, but
I can't think of any reasonable example, were it could make things worse.
> [C++] Status performance optimization from Impala/Kudu
> ------------------------------------------------------
>
> Key: ARROW-3051
> URL: https://issues.apache.org/jira/browse/ARROW-3051
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C++
> Reporter: Wes McKinney
> Priority: Major
> Fix For: 0.11.0
>
>
> Just saw this patch, worth investigating:
> https://github.com/apache/impala/commit/ea615d1d8026dbe1cda3f5c2b048d210b2df435b
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