Alexander Saydakov has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/17869 )

Change subject: IMPALA-10956: datasketches UDFs: memory leak and merge overhead
......................................................................


Patch Set 4:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/17869/4/be/src/exprs/aggregate-functions-ir.cc
File be/src/exprs/aggregate-functions-ir.cc:

http://gerrit.cloudera.org:8080/#/c/17869/4/be/src/exprs/aggregate-functions-ir.cc@2075
PS4, Line 2075:   agg_state_ptr->second = new 
(ctx->Allocate<datasketches::update_theta_sketch>())
              :       datasketches::update_theta_sketch(
              :           datasketches::update_theta_sketch::builder().build())
> I looked through the patch again looking for potential leaks. bit I didn't
Space is allocated just above, and placement new is called to put an object 
there. uninitilaized_fill_n does the same. I just did not quite like using it 
for one object. I think it is clearer to call placement new directly.


http://gerrit.cloudera.org:8080/#/c/17869/4/be/src/exprs/aggregate-functions-ir.cc@2151
PS4, Line 2151:     u.update(*dst_sketch_ptr);
> Couldn't we use std::move here? update seems to be optimized for the rvalue
Yes, we could since we discard this object later. I doubt it makes any 
difference in practice. Rvalue case is supported in the API, but I don't think 
it is handled differently in the Theta union. Anyway, this is not incorrect. In 
the worst case it is a missed slight optimization opportunity.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I8dd0e6736f4266f74f5f265f58d40a4e4707287f
Gerrit-Change-Number: 17869
Gerrit-PatchSet: 4
Gerrit-Owner: Alexander Saydakov <[email protected]>
Gerrit-Reviewer: Alexander Saydakov <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Fucun Chu <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Comment-Date: Fri, 10 Dec 2021 18:16:29 +0000
Gerrit-HasComments: Yes

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