Csaba Ringhofer has posted comments on this change. ( http://gerrit.cloudera.org:8080/19030 )
Change subject: IMPALA-10891: Avoid hash exchanges in more situations ...................................................................... Patch Set 3: (1 comment) http://gerrit.cloudera.org:8080/#/c/19030/3/fe/src/main/java/org/apache/impala/analysis/AggregateInfo.java File fe/src/main/java/org/apache/impala/analysis/AggregateInfo.java: http://gerrit.cloudera.org:8080/#/c/19030/3/fe/src/main/java/org/apache/impala/analysis/AggregateInfo.java@122 PS3, Line 122: highCardinalityExpr = groupingExpr; : break; I am a bit concerned about the simplicity of the logic - what will happen if there are several expression and we find the wrong one with high cardinality? So we return col_1, but the joins before the aggregate create partitions by col_2. -- To view, visit http://gerrit.cloudera.org:8080/19030 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ie627d07b729f1f584f589cd0251dfe2bb64a417f Gerrit-Change-Number: 19030 Gerrit-PatchSet: 3 Gerrit-Owner: Xiaoqing Gao <[email protected]> Gerrit-Reviewer: Csaba Ringhofer <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Comment-Date: Fri, 23 Sep 2022 19:08:19 +0000 Gerrit-HasComments: Yes
