[jira] [Work logged] (HIVE-25879) MetaStoreDirectSql test query should not query the DBS table

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

     [ https://issues.apache.org/jira/browse/HIVE-25879?focusedWorklogId=713214&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-713214 ]

ASF GitHub Bot logged work on HIVE-25879:
-----------------------------------------

                Author: ASF GitHub Bot
            Created on: 22/Jan/22 13:39
            Start Date: 22/Jan/22 13:39
    Worklog Time Spent: 10m 
      Work Description: mszurap opened a new pull request #2964:
URL: https://github.com/apache/hive/pull/2964


   ### What changes were proposed in this pull request?
   Performance optimization: the MetaStoreDirectSql#runTestQuery determines whether the direct SQL can be used. The proposed change is that the VERSION table should be used for this purpose instead of the DBS, which may have significant size.
   
   ### Why are the changes needed?
   Performance improvement. With bigger deployments the test query can run 10x faster (~3 ms instead of 30 ms), and this test query runs for **every** ObjectStore initialization.
   
   ### Does this PR introduce _any_ user-facing change?
   No.
   
   ### How was this patch tested?
   Local cluster. It does not change the functionality, the fix is trivial.


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

            Worklog Id:     (was: 713214)
    Remaining Estimate: 0h
            Time Spent: 10m

> MetaStoreDirectSql test query should not query the DBS table
> ------------------------------------------------------------
>
>                 Key: HIVE-25879
>                 URL: https://issues.apache.org/jira/browse/HIVE-25879
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Miklos Szurap
>            Assignee: Miklos Szurap
>            Priority: Major
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> The runTestQuery() in the org/apache/hadoop/hive/metastore/MetaStoreDirectSql.java is using a test query
> {code:java}
> select "DB_ID" from "DBS"{code}
> to determine whether the direct SQL can be used.
> With larger deployments with many (10k+) Hive databases it would be more efficienct to query a small table instead, for example the "VERSION" table should always have a single row only.



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