Csaba Ringhofer has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/20810 )

Change subject: WIP: Skip KRPC in local exchanges
......................................................................


Patch Set 10:

Ran a perf test (TPCDS-16 without mt_dop): 
https://jenkins.impala.io/job/perf-AB-test/504/console

The results look good but weird:
Delta(Avg): -6.32%  Delta(GeoMean):-3.79%
Many queries have significant improvement and none have significant regression.

Note that the benchmarks runs on a single host with 3 impalads, meaning that 
~1/3 of shuffle happens intra process. Bigger clusters should see less 
improvement.

The weird parts are in the summary changes:
- EXCHANGE SENDERs often became much slower
- most improvement can be seen in non-exchange related nodes, e.g HDFS scan 
nodes

My guess is that most work is saved in threads not visible the profile (KRPC 
receiver side). Probably the queries with the biggest improvements were over 
threaded, and spending less CPU times in these "invisible" threads makes multi 
threaded parts like scanners faster.


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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Iee16cd943d76d04874bce7f3959e74b4685adb6e
Gerrit-Change-Number: 20810
Gerrit-PatchSet: 10
Gerrit-Owner: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Wenzhe Zhou <[email protected]>
Gerrit-Comment-Date: Tue, 19 Dec 2023 06:41:04 +0000
Gerrit-HasComments: No

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