Yifan Zhang has posted comments on this change. ( http://gerrit.cloudera.org:8080/24597 )
Change subject: IMPALA-7996: Optimize constant-false outer joins ...................................................................... Patch Set 1: (1 comment) http://gerrit.cloudera.org:8080/#/c/24597/1/fe/src/main/java/org/apache/impala/planner/SingleNodePlanner.java File fe/src/main/java/org/apache/impala/planner/SingleNodePlanner.java: http://gerrit.cloudera.org:8080/#/c/24597/1/fe/src/main/java/org/apache/impala/planner/SingleNodePlanner.java@2120 PS1, Line 2120: eqJoinConjuncts.add(createNonMatchingEqJoinConjunct(analyzer)); This fix may still cause data skew for FULL OUTER JOIN ON FALSE/NULL: hashing constant keys sends each side to a single executor, limiting distributed parallelism. Perhaps null-extending both sides and combining them with UNION ALL could be considered instead. -- To view, visit http://gerrit.cloudera.org:8080/24597 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I6505825fc958720eec12e13d546661834f221b80 Gerrit-Change-Number: 24597 Gerrit-PatchSet: 1 Gerrit-Owner: Aleksandr Efimov <[email protected]> Gerrit-Reviewer: Aleksandr Efimov <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Michael Smith <[email protected]> Gerrit-Reviewer: Paul Rogers <[email protected]> Gerrit-Reviewer: Yifan Zhang <[email protected]> Gerrit-Comment-Date: Wed, 22 Jul 2026 04:29:05 +0000 Gerrit-HasComments: Yes
