[jira] [Comment Edited] (HIVE-22938) Investigate possibility of removing empty bucket file creation mechanism in Hive-on-MR

["Marton Bod (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-22938?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17051326#comment-17051326 ] 

Marton Bod edited comment on HIVE-22938 at 3/4/20, 3:33 PM:
------------------------------------------------------------

Removing the empty bucket creation logic breaks 400+ tests. At this point with MR being deprecated, the cost/benefit ratio of removing this logic from Hive-on-MR and adjusting all tests accordingly (and running the risk of introducing unforeseen regressions) is not very compelling, so closing this ticket.


was (Author: marton bod):
Removing the empty code part breaks 400+ tests. At this point with MR being deprecated, the cost/benefit ratio of removing this logic from Hive-on-MR and adjusting all tests accordingly (and running the risk of introducing unforeseen regressions) is not very compelling, so closing this ticket.

> Investigate possibility of removing empty bucket file creation mechanism in Hive-on-MR
> --------------------------------------------------------------------------------------
>
>                 Key: HIVE-22938
>                 URL: https://issues.apache.org/jira/browse/HIVE-22938
>             Project: Hive
>          Issue Type: Task
>            Reporter: Marton Bod
>            Assignee: Marton Bod
>            Priority: Major
>         Attachments: HIVE-22938.1.patch
>
>
> As a follow-up to HIVE-22918, this ticket is to investigate whether the empty bucket file creation mechanism can be removed safely when using MR as the engine. 
> For a bucketed table of N buckets, each insert will generate N bucket files in the delta directory, regardless of how many actual buckets are written to. As an example, if a table has 500 buckets, and we insert a single record, 499 empty bucket files are generated alongside the single bucket that contains the actual data. This makes the operation substantially slower in some cases. This behaviour only seems to happen when using MR as the execution engine.
> Some components/parts of the code might depend on this behaviour though, so it needs to be verified that removing this logic does not interfere with anything.



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