[jira] [Commented] (HIVE-4897) Hive should handle AlreadyExists on retries when creating tables/partitions

["David Mollitor (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-4897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17087746#comment-17087746 ] 

David Mollitor commented on HIVE-4897:
--------------------------------------

I think this is often achieved with an 'updated' timestamp value in the database schema.  When a request is generated, the client puts in a timestamp.  If the operation fails and is re-submitted, if the 'updated' timestamp matches the requests then a success is returned, otherwise, if the timestamp in HMS is older, than the retry happens again.

> Hive should handle AlreadyExists on retries when creating tables/partitions
> ---------------------------------------------------------------------------
>
>                 Key: HIVE-4897
>                 URL: https://issues.apache.org/jira/browse/HIVE-4897
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Sergey Shelukhin
>            Assignee: Aihua Xu
>            Priority: Major
>         Attachments: hive-snippet.log
>
>
> Creating new tables/partitions may fail with an AlreadyExistsException if there is an error part way through the creation and the HMS tries again without properly cleaning up or checking if this is a retry.
> While partitioning a new table via a script on distributed hive (MetaStore on the same machine) there was a long timeout and then:
> {code}
> FAILED: Execution Error, return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask. AlreadyExistsException(message:Partition already exists:Partition( ...
> {code}
> I am assuming this is due to retry. Perhaps already-exists on retry could be handled better.
> A similar error occurred while creating a table through Impala, which issued a single createTable call that failed with an AlreadyExistsException. See the logs related to table tmp_proc_8_d2b7b0f133be455ca95615818b8a5879_7 in the attached hive-snippet.log



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