[jira] [Work logged] (HIVE-25492) Major query-based compaction is skipped if partition is empty

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-25492?focusedWorklogId=750290&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-750290 ]

ASF GitHub Bot logged work on HIVE-25492:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 30/Mar/22 17:23
            Start Date: 30/Mar/22 17:23
    Worklog Time Spent: 10m 
      Work Description: asinkovits opened a new pull request #3157:
URL: https://github.com/apache/hive/pull/3157


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   ### What changes were proposed in this pull request?
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   Do not remove empty base directories in the end of a major query based compaction.
   Change how the cleaner collects base/delta/delete delta directories, which are checked if they are eligible for cleaning. 
   
   ### Why are the changes needed?
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   It fixes two issues.
   First if the result of a major query based compaction is empty, the output (empty base directory) was deleted, so you ended up with a NOOP.
   Second, the cleaner did not take into account empty directories. (base/delta/delete delta) So it did not removed old files, even when after the previous fix, the empty base was the latest. It also did not removed empty delta/delete delta directories.
   
   ### Does this PR introduce _any_ user-facing change?
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   No
   
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   Manual + unit tests


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

            Worklog Id:     (was: 750290)
    Remaining Estimate: 0h
            Time Spent: 10m

> Major query-based compaction is skipped if partition is empty
> -------------------------------------------------------------
>
>                 Key: HIVE-25492
>                 URL: https://issues.apache.org/jira/browse/HIVE-25492
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Karen Coppage
>            Assignee: Antal Sinkovits
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> Currently if the result of query-based compaction is an empty base, delta, or delete delta, the empty directory is deleted.
> This is because of minor compaction – if there are only deltas to compact, then no compacted delete delta should be created (only a compacted delta). In the same way, if there are only delete deltas to compact, then no compacted delta should be created (only a compacted delete delta).
> There is an issue with major compaction. If all the data in the partition has been deleted, then we should get an empty base directory after compaction. Instead, the empty base directory is deleted because it's empty and compaction claims to succeed but we end up with the same deltas/delete deltas we started with – basically compaction does not run.
> Where to start? MajorQueryCompactor#commitCompaction



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