Qifan Chen has posted comments on this change. ( http://gerrit.cloudera.org:8080/16266 )
Change subject: IMPALA-5022 part 1/2: Outer join simplification ...................................................................... Patch Set 16: (5 comments) Looks good to me! http://gerrit.cloudera.org:8080/#/c/16266/16//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/16266/16//COMMIT_MSG@9 PS16, Line 9: As a general rule, an outer join can be converted to an inner join if : there is a condition on the inner table that filters out non‑matching : rows. In a left outer join, the right table is the inner table, while : it is the left table in a right outer join. In a full outer join, both : tables are inner tables. Conditions that are FALSE for nulls are : referred to as null filtering conditions, and these are the conditions : that enable the outer‑to‑inner join conversion to be made. Maybe reworded as "Outer joins in SQL can return rows with certain columns filled with NULLs when a match can not be found. However, such rows can be rejected by null-rejecting predicates. The conditions in a null-rejecting predicate that are always evaluated to FALSE for NULLs are referred to as null-filtering conditions. In general, an outer join can be converted to an inner join if there exist null-filtering conditions on the inner tables. In a left outer join, the right table is the inner table, while in a right outer join it is the left table. In a full outer join, both tables are inner tables." http://gerrit.cloudera.org:8080/#/c/16266/16//COMMIT_MSG@50 PS16, Line 50: I think we need to add a high-level description of what work is done in this commit. And also what will be the part 2 work. http://gerrit.cloudera.org:8080/#/c/16266/13/fe/src/main/java/org/apache/impala/analysis/Analyzer.java File fe/src/main/java/org/apache/impala/analysis/Analyzer.java: http://gerrit.cloudera.org:8080/#/c/16266/13/fe/src/main/java/org/apache/impala/analysis/Analyzer.java@3277 PS13, Line 3277: */ : private boolean isNullableConjunct(Expr e, List<TupleId> tupleIds) { : // A clause like "t1.v1 IS NOT NULL OR t2.v2 IS NOT NULL" and t1 in 'tupleIds' does : // not prove that t1.v1 can't be NULL, because when t2.v2 IS NOT NULL, t1.v1 can be : // null. But a clause like "t1.v1 IS NOT NULL OR t1.v2 IS NOT NULL" proves that the : // t1 row as a whole can't be all-NULL. : Lis > I changed to use the set retainAll method, but we should collect all of the OK. It sounds like test in one shot for t1.id>10 and t2.id<10 or t2.id>50 or t2.name='a' will not work. http://gerrit.cloudera.org:8080/#/c/16266/12/fe/src/main/java/org/apache/impala/analysis/FunctionCallExpr.java File fe/src/main/java/org/apache/impala/analysis/FunctionCallExpr.java: http://gerrit.cloudera.org:8080/#/c/16266/12/fe/src/main/java/org/apache/impala/analysis/FunctionCallExpr.java@321 PS12, Line 321: Condition nit. "Conditional" http://gerrit.cloudera.org:8080/#/c/16266/12/fe/src/main/java/org/apache/impala/analysis/FunctionCallExpr.java@327 PS12, Line 327: f > OK, I see. I changed this as the doc. But I think the 'case' is not Functio Done -- To view, visit http://gerrit.cloudera.org:8080/16266 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Iaa7804033fac68e93f33c387dc68ef67f803e93e Gerrit-Change-Number: 16266 Gerrit-PatchSet: 16 Gerrit-Owner: Xianqing He <hexianqing...@126.com> Gerrit-Reviewer: Impala Public Jenkins <impala-public-jenk...@cloudera.com> Gerrit-Reviewer: Qifan Chen <qc...@cloudera.com> Gerrit-Reviewer: Shant Hovsepian <sh...@cloudera.com> Gerrit-Reviewer: Xianqing He <hexianqing...@126.com> Gerrit-Comment-Date: Mon, 31 Aug 2020 15:13:09 +0000 Gerrit-HasComments: Yes
