[jira] [Updated] (HIVE-15808) Remove semijoin reduction branch if it is on bigtable along with hash join

["Deepak Jaiswal (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-15808?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Deepak Jaiswal updated HIVE-15808:
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    Description: If there is a semijoin branch on the same operator pipeline which contains a hash join then it is by design on big table which is not optimal. The operator cycle detection logic may not find a cycle as there is no cycle at operator level. However, once Tez builds its task there can be a cycle at task level causing the query to fail.  (was: It is found that the current logic of cycle detection does not find cycles created when there is a semijoin branch parallel to a hash join on a reducer.
To avoid such cycles, remove the semijoin reduction optimization.)
        Summary: Remove semijoin reduction branch if it is on bigtable along with hash join  (was: Remove Semijoin reduction branch on reducers if there is hash join)

> Remove semijoin reduction branch if it is on bigtable along with hash join
> --------------------------------------------------------------------------
>
>                 Key: HIVE-15808
>                 URL: https://issues.apache.org/jira/browse/HIVE-15808
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Deepak Jaiswal
>            Assignee: Deepak Jaiswal
>         Attachments: HIVE-15808.patch
>
>
> If there is a semijoin branch on the same operator pipeline which contains a hash join then it is by design on big table which is not optimal. The operator cycle detection logic may not find a cycle as there is no cycle at operator level. However, once Tez builds its task there can be a cycle at task level causing the query to fail.



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