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From "Remus Rusanu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-5817) column name to index mapping in VectorizationContext is broken
Date Mon, 25 Nov 2013 15:25:35 GMT

    [ https://issues.apache.org/jira/browse/HIVE-5817?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13831541#comment-13831541
] 

Remus Rusanu commented on HIVE-5817:
------------------------------------

I have  the implementation of 'vectorization regions" almost done and I know how to finish
it. Will post a patch tomorrow. 

Using the qualified column names (alias + column) will work probably, I don't think a query
can have duplicate aliases (not up to par on my ANSI readings one can tell...). Thing is that
will ripple everywhere in the vectorization context, we'll have to modify all the expression
builders to use the alias.column as a key. If the "region concept" will work, will have a
much more contained impact.

> column name to index mapping in VectorizationContext is broken
> --------------------------------------------------------------
>
>                 Key: HIVE-5817
>                 URL: https://issues.apache.org/jira/browse/HIVE-5817
>             Project: Hive
>          Issue Type: Bug
>          Components: Vectorization
>            Reporter: Sergey Shelukhin
>            Assignee: Remus Rusanu
>            Priority: Critical
>         Attachments: HIVE-5817-uniquecols.broken.patch, HIVE-5817.00-broken.patch
>
>
> Columns coming from different operators may have the same internal names ("_colNN").
There exists a query in the form {{select b.cb, a.ca from a JOIN b ON ... JOIN x ON ...;}}
 (distilled from a more complex query), which runs ok w/o vectorization. With vectorization,
it will run ok for most ca, but for some ca it will fail (or can probably return incorrect
results). That is because when building column-to-VRG-index map in VectorizationContext, internal
column name for ca that the first map join operator adds to the mapping may be the same as
internal name for cb that the 2nd one tries to add. 2nd VMJ doesn't add it (see code in ctor),
and when it's time for it to output stuff, it retrieves wrong index from the map by name,
and then wrong vector from VRG.



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