Qifan Chen has posted comments on this change. ( http://gerrit.cloudera.org:8080/17396 )
Change subject: IMPALA-10197: Add KUDU_REPLICA_SELECTION query option ...................................................................... Patch Set 2: (2 comments) Thanks Wenzhe for the reply. http://gerrit.cloudera.org:8080/#/c/17396/2/fe/src/main/java/org/apache/impala/planner/KuduScanNode.java File fe/src/main/java/org/apache/impala/planner/KuduScanNode.java: http://gerrit.cloudera.org:8080/#/c/17396/2/fe/src/main/java/org/apache/impala/planner/KuduScanNode.java@237 PS2, Line 237: if (leadOnly && !replica.getRole().equals(Role.LEADER.toString())) continue; > The code tablet.getReplicas() and replica.getRole() are calling Kudu client Done http://gerrit.cloudera.org:8080/#/c/17396/2/testdata/workloads/functional-planner/queries/PlannerTest/kudu-replica-selection-leader-only.test File testdata/workloads/functional-planner/queries/PlannerTest/kudu-replica-selection-leader-only.test: http://gerrit.cloudera.org:8080/#/c/17396/2/testdata/workloads/functional-planner/queries/PlannerTest/kudu-replica-selection-leader-only.test@9 PS2, Line 9: 00:SCAN KUDU [functional_kudu.zipcode_incomes] : kudu predicates: id = '8600000US00601' : mem-estimate=3.75MB mem-reservation=0B thread-reservation=1 : tuple-ids=0 row-size=124B cardinality=1 : in pipelines: 00(GETNEXT) > The role of Kudu replica is not shown in the explain output. The difference Maybe we just annotate the kudu scan for LEADER-only, something like the following? 00:SCAN KUDU [functional_kudu.zipcode_incomes, LEADER-only] kudu predicates: id = '8600000US00601' mem-estimate=3.75MB mem-reservation=0B thread-reservation=1 tuple-ids=0 row-size=124B cardinality=1 in pipelines: 00(GETNEXT) Knowing the scan target is very useful info for performance tuning. For one thing, restricting to LEADER(s) may cause contention in a heavy concurrency situation. -- To view, visit http://gerrit.cloudera.org:8080/17396 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I613e6d9be8680c05880f7cf962a31aa38931f3d9 Gerrit-Change-Number: 17396 Gerrit-PatchSet: 2 Gerrit-Owner: Wenzhe Zhou <wz...@cloudera.com> Gerrit-Reviewer: Grant Henke <granthe...@apache.org> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Joe McDonnell <joemcdonn...@cloudera.com> Gerrit-Reviewer: Qifan Chen <qc...@cloudera.com> Gerrit-Reviewer: Wenzhe Zhou <wz...@cloudera.com> Gerrit-Comment-Date: Wed, 19 May 2021 18:22:00 +0000 Gerrit-HasComments: Yes
