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https://issues.apache.org/jira/browse/HIVE-518?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12713419#action_12713419
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Namit Jain commented on HIVE-518:
---------------------------------

I agree with it - it will not lead to any problem since the join results will 
be empty in both the new and
the old drop, but the whole purpose of testing may be lost.

Hinting seems useless, because if the pipelines can be modified to add query 
level hints, the queries themselves
can be modified.

Via a configuration parameter, the list of tables can be specified and sampling 
may only        be applicable to
those tables. It will need the pipelines to be modified, or we can take a more 
aggressive approach and add
sampling to all tables unless the user asks us not to do so. This way, only the 
offending pipelines (for eg.
the one pointed by Raghu) needs to be modified.


> test mode in hive
> -----------------
>
>                 Key: HIVE-518
>                 URL: https://issues.apache.org/jira/browse/HIVE-518
>             Project: Hadoop Hive
>          Issue Type: Bug
>          Components: Query Processor
>    Affects Versions: 0.3.1
>            Reporter: Namit Jain
>            Assignee: Namit Jain
>             Fix For: 0.4.0
>
>         Attachments: hive.518.1.patch, hive.518.2.patch
>
>
> It would be good to have a test mode in hive - this will help in checking the 
> validity of a hive drop on a production cluster.
> The following would be good to have:
> Testmode --> In testmode, all input tables are sampled (if not already 
> sampled) and all output tables are prefixed by a user supplied name.
> This way, multiple hive drops can be compared quickly for correctness

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