Zoltan Borok-Nagy has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/21597 )

Change subject: IMPALA-13246: Smallify strings during broadcast exchange
......................................................................


Patch Set 4:

(5 comments)

Thanks for working on this!

http://gerrit.cloudera.org:8080/#/c/21597/4//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/21597/4//COMMIT_MSG@14
PS4, Line 14: it turned out that this is not true in
            :   Iceberg's delete's directed shuffle
Could you please add more details for this? In DIRECTED mode I wouldn't expect 
any smallifications as paths are usally larger than 11 characters.


http://gerrit.cloudera.org:8080/#/c/21597/4//COMMIT_MSG@17
PS4, Line 17: Measured >1% improvement in TPCH(42).
Above you mentioned that removing Tuple::SmallifyStrings() makes TPC-H slower. 
Do you mean that removing Tuple::SmallifyStrings() is a bit slower, but still 
this change is faster in overall? Please add clarification.


http://gerrit.cloudera.org:8080/#/c/21597/4/be/src/runtime/tuple.h
File be/src/runtime/tuple.h:

http://gerrit.cloudera.org:8080/#/c/21597/4/be/src/runtime/tuple.h@123
PS4, Line 123: =false
IMO the default parameter makes the code a bit unsafe, as it is too easy to 
write TotalByteSize(tuple_desc) without thinking about what should be the value 
for 'assume_smallify'. Also, TotalByteSize() doesn't seem to be called in so 
many places that would justify the default parameter.


http://gerrit.cloudera.org:8080/#/c/21597/4/be/src/runtime/tuple.h@140
PS4, Line 140:
nit: redundant space


http://gerrit.cloudera.org:8080/#/c/21597/4/be/src/runtime/tuple.cc
File be/src/runtime/tuple.cc:

http://gerrit.cloudera.org:8080/#/c/21597/4/be/src/runtime/tuple.cc@68
PS4, Line 68: string_val->Len() <= SmallableString::SMALL_LIMIT
nit: you could add a method 'PossibleToSmallify()' or 'FitToSmall()' to 
StringValue



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I281d77c7a241ebfe8716eb5c975f0660601aec1b
Gerrit-Change-Number: 21597
Gerrit-PatchSet: 4
Gerrit-Owner: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Zoltan Borok-Nagy <[email protected]>
Gerrit-Comment-Date: Mon, 12 Aug 2024 17:17:57 +0000
Gerrit-HasComments: Yes

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