Tim Armstrong has posted comments on this change. ( http://gerrit.cloudera.org:8080/16115 )
Change subject: IMPALA-9898: Plan generation and execution for grouping sets ...................................................................... Patch Set 3: (1 comment) http://gerrit.cloudera.org:8080/#/c/16115/3/fe/src/main/java/org/apache/impala/analysis/MultiAggregateInfo.java File fe/src/main/java/org/apache/impala/analysis/MultiAggregateInfo.java: http://gerrit.cloudera.org:8080/#/c/16115/3/fe/src/main/java/org/apache/impala/analysis/MultiAggregateInfo.java@339 PS3, Line 339: // Register value transfers to allow predicate assignment through GROUP BY. I discovered a bug here with the below query where it's not safe to push the predicate through a group by with grouping sets since output columns may be NULL even if the input is non-NULL. I think it's a similar challenge to pushing predicates through outer joins. The obvious fix that I can see is just to not add these equivalences. I think it's safe if the column is present in all grouping sets, but I think that's probably not a common case. explain select int_col, count(*) from alltypesagg group by rollup(int_col) having int_col is NULL -- To view, visit http://gerrit.cloudera.org:8080/16115 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Id474c5373860b0d8014ee9c844a3fb90092be968 Gerrit-Change-Number: 16115 Gerrit-PatchSet: 3 Gerrit-Owner: Aman Sinha <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Comment-Date: Wed, 01 Jul 2020 22:00:15 +0000 Gerrit-HasComments: Yes
