Tim Armstrong 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_
> I'm not sure there is an extra indirection in this case - the  comparator i
presumably beforehand the comparator passed to STL was a value, and we're now 
passing a pointer to that value (inside the Wraper class), so I think there's 
an extra pointer it has to traverse. It seems like overall this is a 
performance win, but I'm just wary that this code seems to be gradually growing 
additional indirection.


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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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