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https://issues.apache.org/jira/browse/IMPALA-12390?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17766838#comment-17766838
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ASF subversion and git services commented on IMPALA-12390:
----------------------------------------------------------

Commit 3614a6a776819a1e918ce7fe833cd9e916d6002a in impala's branch 
refs/heads/master from gaurav1086
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=3614a6a77 ]

IMPALA-12390 (part 2): Enable some clang-tidy performance related checks

This enables the clang tidy performance check:
performance-inefficient-string-concatenation
"warning: string concatenation results in allocation of unnecessary
temporary strings"
Fix: Use StrCat() to concatenate multiple strings

Testing:
 - Ran bin/run_clang_tidy.sh with the new checks
 - Ran GVO

Change-Id: Ibad8bd0f12aab92ad874f5a6b9ec922dce7f3190
Reviewed-on: http://gerrit.cloudera.org:8080/20445
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>


> Enable performance related clang-tidy checks
> --------------------------------------------
>
>                 Key: IMPALA-12390
>                 URL: https://issues.apache.org/jira/browse/IMPALA-12390
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Backend
>    Affects Versions: Impala 4.3.0
>            Reporter: Joe McDonnell
>            Assignee: Joe McDonnell
>            Priority: Major
>             Fix For: Impala 4.3.0
>
>
> clang-tidy has several performance-related checks that seem like they would 
> be useful to enforce. Here are some examples:
> {noformat}
> /home/joemcdonnell/upstream/Impala/be/src/runtime/types.h:313:25: warning: 
> loop variable is copied but only used as const reference; consider making it 
> a const reference [performance-for-range-copy]
>         for (ColumnType child_type : col_type.children) {
>              ~~~~~~~~~~ ^
>              const &
> /home/joemcdonnell/upstream/Impala/be/src/catalog/catalog-util.cc:168:34: 
> warning: 'find' called with a string literal consisting of a single 
> character; consider using the more effective overload accepting a character 
> [performance-faster-string-find]
>       int pos = object_name.find(".");
>                                  ^~~~
>                                  '.'
> /home/joemcdonnell/upstream/Impala/be/src/util/decimal-util.h:55:53: warning: 
> the parameter 'b' is copied for each invocation but only used as a const 
> reference; consider making it a const reference 
> [performance-unnecessary-value-param]
>   static int256_t SafeMultiply(int256_t a, int256_t b, bool may_overflow) {
>                                            ~~~~~~~~ ^
>                                            const &
> /home/joemcdonnell/upstream/Impala/be/src/codegen/llvm-codegen.cc:847:5: 
> warning: 'push_back' is called inside a loop; consider pre-allocating the 
> vector capacity before the loop [performance-inefficient-vector-operation]
>     arguments.push_back(args_[i].type);
>     ^{noformat}
> In all, they seem to flag things that developers wouldn't ordinarily notice, 
> and it doesn't seem to have too many false positives. We should look into 
> enabling these.



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