[teiid-issues] [JBoss JIRA] (TEIID-3580) Hive 0.13.1 JDBC jars makes queries run slow

[Steven Hawkins (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-3580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13091496#comment-13091496 ] 

Steven Hawkins commented on TEIID-3580:
---------------------------------------

> Very interesting Steven! I executed the query "SELECT g_0.code, g_0.description, g_0.total_emp, g_0.salary FROM sample_07 AS g_0" from the web app and its taking the same 20 seconds to return. I run the same query from a standalone JDBC project and the delay is the same : 20+ second.

Excellent.  That greatly simplifies the approach to working the issue.

> Whats your guess about what is happening ?

I couldn't really say.  A guess would be that the driver is doing some upfront resolving when the column names are specified vs. select *.  If the delay only happens one time, then the driver is likely pulling/caching some metastore information.  If it's happening every time, then it's likely that something is wrong with the metastore.

> So it safe to assume that the culprit is somewhere in the jars ?

I'm not sure that's yet clear either.  But at least it will simpler to iterate on as a standalone project to see if different jar versions make a difference.

> Hive 0.13.1 JDBC jars makes queries run slow
> --------------------------------------------
>
>                 Key: TEIID-3580
>                 URL: https://issues.jboss.org/browse/TEIID-3580
>             Project: Teiid
>          Issue Type: Bug
>          Components: Query Engine
>    Affects Versions: 8.7.3
>            Reporter: Debbie Steigner
>            Assignee: Steven Hawkins
>         Attachments: threaddump-1437508266001.tdump
>
>
> When using the JDBC jars for Hive 0.13.1 running on HDP 2.1, queries executed against table 'default.sample_07' takes approximately 20-30 seconds to return.
> The Hive JDBC jars for version 0.13.1 can be found here :
> https://github.com/vchintal/hive-jdbc-jars-archive
> Alternatively a ready-to-go modules can be downloaded from here for testing:
> https://drive.google.com/file/d/0BxJhoZ1V34QHSmgzTlBRVktZaGM/
> Use the following driver snippet when using the above mentioned module:
> <driver name="hive" module="org.apache.hadoop.hive:0.13.1">
>       <driver-class>org.apache.hive.jdbc.HiveDriver</driver-class>
> </driver>



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