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https://issues.apache.org/jira/browse/HIVE-21487?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16798224#comment-16798224
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Todd Lipcon commented on HIVE-21487:
------------------------------------

Seems that this cluster is in some state where all compactions are failing (I 
think due to some other testing going on with a strange setup). The query is 
likely coming from CompactionTxnHandler.checkFailedCompactions.

It's possible this isn't a hot enough code path to be worth a really large 
index, but perhaps it's worth one at least on ethe database/table level.

> COMPLETED_COMPACTIONS table missing appropriate indexes
> -------------------------------------------------------
>
>                 Key: HIVE-21487
>                 URL: https://issues.apache.org/jira/browse/HIVE-21487
>             Project: Hive
>          Issue Type: Bug
>    Affects Versions: 3.1.1
>            Reporter: Todd Lipcon
>            Priority: Major
>
> Looking at a MySQL install where HMS is pointed on Hive 3.1, I see a constant 
> stream of queries of the form:
> {code}
> select CC_STATE from COMPLETED_COMPACTIONS where CC_DATABASE = 
> 'tpcds_orc_exact_1000' and CC_TABLE = 'catalog_returns' and CC_PARTITION = 
> 'cr_returned_date_sk=2452851' and CC_STATE != 'a' order by CC_ID desc;
> {code}
> but the COMPLETED_COMPACTIONS table has no index. In this case it's resulting 
> in a full table scan over 115k rows, which takes around 100ms.



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