[jira] [Work logged] (HIVE-24589) Drop catalog failing with deadlock error for Oracle backend dbms.

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     [ https://issues.apache.org/jira/browse/HIVE-24589?focusedWorklogId=534356&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-534356 ]

ASF GitHub Bot logged work on HIVE-24589:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 11/Jan/21 17:18
            Start Date: 11/Jan/21 17:18
    Worklog Time Spent: 10m 
      Work Description: maheshk114 opened a new pull request #1850:
URL: https://github.com/apache/hive/pull/1850


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Issue Time Tracking
-------------------

            Worklog Id:     (was: 534356)
    Remaining Estimate: 0h
            Time Spent: 10m

> Drop catalog failing with deadlock error for Oracle backend dbms.
> -----------------------------------------------------------------
>
>                 Key: HIVE-24589
>                 URL: https://issues.apache.org/jira/browse/HIVE-24589
>             Project: Hive
>          Issue Type: Bug
>            Reporter: mahesh kumar behera
>            Assignee: mahesh kumar behera
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> When we do a drop catalog we drop the catalog from the CTLGS table. The DBS table has a foreign key reference on CTLGS for CTLG_NAME. This is causing the DBS table to be locked exclusively and causing deadlocks. This can be avoided by creating an index in the DBS table on CTLG_NAME.
> {code:java}
> CREATE INDEX CTLG_NAME_DBS ON DBS(CTLG_NAME); {code}
> {code:java}
>  Oracle Database maximizes the concurrency control of parent keys in relation to dependent foreign keys.Locking behaviour depends on whether foreign key columns are indexed. If foreign keys are not indexed, then the child table will probably be locked more frequently, deadlocks will occur, and concurrency will be decreased. For this reason foreign keys should almost always be indexed. The only exception is when the matching unique or primary key is never updated or deleted.{code}
>  



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