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

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

     [ https://issues.apache.org/jira/browse/HIVE-25879?focusedWorklogId=778978&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-778978 ]

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

                Author: ASF GitHub Bot
            Created on: 07/Jun/22 10:36
            Start Date: 07/Jun/22 10:36
    Worklog Time Spent: 10m 
      Work Description: mszurap opened a new pull request, #3348:
URL: https://github.com/apache/hive/pull/3348

   ### What changes were proposed in this pull request?
   Performance optimization: the MetaStoreDirectSql#runTestQuery determines whether the direct SQL can be used. Before the fix the code queries the whole DBS table without any filters. The proposed change is to add a filter "WHERE DB_ID=1" which should be fast as it is the primary key for that table.
   
   
   ### 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?
   In my local dev env I've run the "mvn test" successfully in the "standalone-metastore".




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

    Worklog Id:     (was: 778978)
    Time Spent: 1h  (was: 50m)

> MetaStoreDirectSql test query should not query the whole DBS table
> ------------------------------------------------------------------
>
>                 Key: HIVE-25879
>                 URL: https://issues.apache.org/jira/browse/HIVE-25879
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Miklos Szurap
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 1h
>  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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