Jim Apple has posted comments on this change.

Change subject: IMPALA-3375: Improve TopN performance with a trivial Compare 
object.
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Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/2918/1/be/src/util/tuple-row-compare.h
File be/src/util/tuple-row-compare.h:

Line 143: codegend_compare_fn_
> presumably beforehand the comparator passed to STL was a value, and we're n
Good point. I think, in order to fix this, we could pass around a struct of 
pointers to the member variables, then call the function on them, etc. Given 
that the patch (as written) seems to be strictly an improvement in the run time 
of queries, I'd prefer to leave this as a TODO in the code.

Thoughts?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I24755227b5bbbca6ad7c7d31d9bb8e132ca89e11
Gerrit-PatchSet: 1
Gerrit-Project: Impala
Gerrit-Branch: master
Gerrit-Owner: Jim Apple <[email protected]>
Gerrit-Reviewer: Alex Behm <[email protected]>
Gerrit-Reviewer: Dan Hecht <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Mostafa Mokhtar <[email protected]>
Gerrit-Reviewer: Tim Armstrong <[email protected]>
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