Aman Sinha has posted comments on this change. ( http://gerrit.cloudera.org:8080/21860 )
Change subject: IMPALA-13405: Do tuple analysis to lower AggregationNode cardinality ...................................................................... Patch Set 11: (2 comments) http://gerrit.cloudera.org:8080/#/c/21860/11//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/21860/11//COMMIT_MSG@12 PS11, Line 12: AggragationNode nit: typo "AggragationNode" -> AggregationNode http://gerrit.cloudera.org:8080/#/c/21860/11/fe/src/main/java/org/apache/impala/planner/AggregationNode.java File fe/src/main/java/org/apache/impala/planner/AggregationNode.java: http://gerrit.cloudera.org:8080/#/c/21860/11/fe/src/main/java/org/apache/impala/planner/AggregationNode.java@368 PS11, Line 368: List<PlanNode> postOrderNodes = planNode.getNodesPostOrder(); Just thinking about a more complex plan where we have nested subqueries or views. In this, there will be repeated post order traversals of the sub trees for each level of the group-by. For example: create view v1 as select a, b, c, count(*) from t1 inner join t2 on t1.x = t2.y group by a, b, c; create view v2 as select a, b, count(*) from v1 group by a, b; select a, count(*) from v2 group by a; For doing the estimate of the outermost query, it would do a traversal of v2 and v1, although v1 would have already been traversed when v2's cardinality was estimated. For TPC-DS, this may not be a concern but just thinking about other scenarios. The tradeoff of extra compilation time may be acceptable but just want to bring up for discussion. -- To view, visit http://gerrit.cloudera.org:8080/21860 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Icd589ab5f7ba9566a0d35784f61f5ffaef5696e7 Gerrit-Change-Number: 21860 Gerrit-PatchSet: 11 Gerrit-Owner: Riza Suminto <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Michael Smith <[email protected]> Gerrit-Reviewer: Riza Suminto <[email protected]> Gerrit-Reviewer: Yida Wu <[email protected]> Gerrit-Comment-Date: Thu, 17 Oct 2024 17:57:06 +0000 Gerrit-HasComments: Yes
