[jira] [Work started] (HIVE-13069) Enable cartesian product merging
[ https://issues.apache.org/jira/browse/HIVE-13069?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Work on HIVE-13069 started by Jesus Camacho Rodriguez. -- > Enable cartesian product merging > > > Key: HIVE-13069 > URL: https://issues.apache.org/jira/browse/HIVE-13069 > Project: Hive > Issue Type: Improvement > Components: Parser >Reporter: Jesus Camacho Rodriguez >Assignee: Jesus Camacho Rodriguez > Attachments: HIVE-13069.01.patch, HIVE-13069.patch > > > Currently we can merge 2-way joins into n-way joins when the joins are > executed over the same column. > In turn, CBO might produce plans containing cartesian products if the join > columns are constant values; after HIVE-12543 went in, this is rather common, > as those constant columns are correctly pruned. However, currently we do not > merge a cartesian product with two inputs into a cartesian product with > multiple inputs, which could result in performance loss. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
[jira] [Work started] (HIVE-13069) Enable cartesian product merging
[ https://issues.apache.org/jira/browse/HIVE-13069?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Work on HIVE-13069 started by Jesus Camacho Rodriguez. -- > Enable cartesian product merging > > > Key: HIVE-13069 > URL: https://issues.apache.org/jira/browse/HIVE-13069 > Project: Hive > Issue Type: Improvement > Components: Parser >Reporter: Jesus Camacho Rodriguez >Assignee: Jesus Camacho Rodriguez > > Currently we can merge 2-way joins into n-way joins when the joins are > executed over the same column. > In turn, CBO might produce plans containing cartesian products if the join > columns are constant values; after HIVE-12543 went in, this is rather common, > as those constant columns are correctly pruned. However, currently we do not > merge a cartesian product with two inputs into a cartesian product with > multiple inputs, which could result in performance loss. -- This message was sent by Atlassian JIRA (v6.3.4#6332)
