[jira] [Created] (HIVE-22938) Investigate possibility of removing empty bucket file creation mechanism in MR

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

Marton Bod created HIVE-22938:
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             Summary: Investigate possibility of removing empty bucket file creation mechanism in MR
                 Key: HIVE-22938
                 URL: https://issues.apache.org/jira/browse/HIVE-22938
             Project: Hive
          Issue Type: Task
            Reporter: Marton Bod


As a follow-up to [HIVE-22918|https://issues.apache.org/jira/browse/HIVE-22918], this ticket is to investigate whether the empty bucket file creation mechanism can be removed safely from MR. 

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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