Qifan Chen has posted comments on this change. ( http://gerrit.cloudera.org:8080/18327 )
Change subject: IMPALA-11123: Optimize count(star) for ORC scans ...................................................................... Patch Set 8: Code-Review+1 (7 comments) Looks great! http://gerrit.cloudera.org:8080/#/c/18327/8//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/18327/8//COMMIT_MSG@9 PS8, Line 9: IMPALA-5036 added optimization for count(star) in Parquet scans that : avoid materializing dummy rows. nit. This patch provides count(star) optimization for ORC scans, similar to the work done in IMPALA-5036 for Parquet scans. http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test File testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test: http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@3 PS8, Line 3: # a text table, so the optimization is not applied. nit. May add a comment: The optimization is observed when the cardinality of the ORC scan (24) is the same as the # of files (24). http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@126 PS8, Line 126: should be nit. is http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@168 PS8, Line 168: there are two aggregate functions nit. it can not be applied to the 1st aggregate function. http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@181 PS8, Line 181: because the inner count(*) is not materialized. The outer : # count(*) does not reference a base table. nit. The optimization does apply to the inner count(*). http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@277 PS8, Line 277: there nit. all predicates are on partition columns only. http://gerrit.cloudera.org:8080/#/c/18327/8/testdata/workloads/functional-planner/queries/PlannerTest/orc-stats-agg.test@386 PS8, Line 386: # Optimization is not applied when there is a distinct agg. nit. in general. -- To view, visit http://gerrit.cloudera.org:8080/18327 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I0fafa1182f97323aeb9ee39dd4e8ecd418fa6091 Gerrit-Change-Number: 18327 Gerrit-PatchSet: 8 Gerrit-Owner: Riza Suminto <[email protected]> Gerrit-Reviewer: Csaba Ringhofer <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Qifan Chen <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: Riza Suminto <[email protected]> Gerrit-Comment-Date: Wed, 30 Mar 2022 18:19:12 +0000 Gerrit-HasComments: Yes
