Krisztian Kasa created HIVE-26524: ------------------------------------- Summary: Use Calcite to remove sections of a query plan known never produces rows Key: HIVE-26524 URL: https://issues.apache.org/jira/browse/HIVE-26524 Project: Hive Issue Type: Improvement Components: CBO Reporter: Krisztian Kasa Assignee: Krisztian Kasa
Calcite has a set of rules to remove sections of a query plan known never produces any rows. In some cases the whole plan can be removed. Such plans are represented with a single {{Values}} operators with no tuples. ex.: {code} select y + 1 from (select a1 y, b1 z from t1 where b1 > 10) q WHERE 1=0 {code} {code} HiveValues(tuples=[[]]) {code} Other cases when plan has outer join or set operators some branches can be replaced with empty values moving forward the join/set operator can be removed {code} select a2, b2 from t2 where 1=0 union select a1, b1 from t1 {code} {code} HiveAggregate(group=[{0, 1}]) HiveTableScan(table=[[default, t1]], table:alias=[t1]) {code} -- This message was sent by Atlassian Jira (v8.20.10#820010)