Csaba Ringhofer has posted comments on this change. ( http://gerrit.cloudera.org:8080/19682 )
Change subject: IMPALA-12006: Improve cardinality estimation for joins involving multiple conjuncts ...................................................................... Patch Set 1: (4 comments) http://gerrit.cloudera.org:8080/#/c/19682/1/fe/src/main/java/org/apache/impala/planner/JoinNode.java File fe/src/main/java/org/apache/impala/planner/JoinNode.java: http://gerrit.cloudera.org:8080/#/c/19682/1/fe/src/main/java/org/apache/impala/planner/JoinNode.java@421 PS1, Line 421: if (analyzer.getQueryOptions().isUse_multiplied_selectivity_for_join()) { > It would be more flexible to allow a correlation coefficient between 0-1 he +1 for making this more flexible http://gerrit.cloudera.org:8080/#/c/19682/3/fe/src/main/java/org/apache/impala/planner/JoinNode.java File fe/src/main/java/org/apache/impala/planner/JoinNode.java: http://gerrit.cloudera.org:8080/#/c/19682/3/fe/src/main/java/org/apache/impala/planner/JoinNode.java@414 PS3, Line 414: checkedMultiply Hitting the limit seems possible here with big RHS+LHS and could lead to weird results when we devide with total_rows. Maybe we could use a double here or divide with lhsCard and rhsCard instead of total_rows? http://gerrit.cloudera.org:8080/#/c/19682/3/fe/src/main/java/org/apache/impala/planner/JoinNode.java@434 PS3, Line 434: This seems to be the same logic as in the loop above. I think that it would easier to understand if the joinCards were collected in a list first and then a loop would combine the values. http://gerrit.cloudera.org:8080/#/c/19682/3/fe/src/main/java/org/apache/impala/planner/JoinNode.java@443 PS3, Line 443: Preconditions.checkState(result >= 0); This could be moved to line 430. -- To view, visit http://gerrit.cloudera.org:8080/19682 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I845d778a58404af834f7501fc8157a5a4b4bcc35 Gerrit-Change-Number: 19682 Gerrit-PatchSet: 1 Gerrit-Owner: Aman Sinha <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Csaba Ringhofer <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Kurt Deschler <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Comment-Date: Wed, 05 Apr 2023 15:56:25 +0000 Gerrit-HasComments: Yes
