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From Daniel Barclay <dbarc...@maprtech.com>
Subject Re: [Discuss] Hive - Smallint and Tinyint
Date Mon, 08 Jun 2015 20:51:26 GMT
Note DRILL-2470, "Implement SMALLINT and TINYINT [umbrella]".

Jacques Nadeau wrote:
> I think it would be worthwhile to first open up a set of JIRAs associated
> with finishing support for these datatypes.  I'm guessing the scale of
> effort is less than one might initially guess.  Once those are opened, it
> would be easier to give feedback on the relative merit of that work versus
> the alternative solution you suggested.
>
> On Mon, Jun 8, 2015 at 11:12 AM, Jason Altekruse <altekrusejason@gmail.com>
> wrote:
>
>> Hello Drillers,
>>
>> I have been working on DRILL-3209, which aims to speed up reading from hive
>> tables by re-planning them as native Drill reads in the case where the
>> tables are backed by files that have available native readers. This will
>> begin with parquet and delimited text files.
>>
>> To provide the same behavior as reading through the Serde interface, I must
>> insert a cast above the read operation to provide the same types that the
>> Hive scan otherwise would.
>>
>> The issue I am seeing is that Hive appears to be reading into both the
>> tinyint and smallint types which I believe are not fully supported
>> (currently my new injected project is failing to find a function to cast to
>> tinyint). See the unsupported note in the docs here [1] for smallint,
>> tinyint is not even listed.
>>
>> I can simply add the function to provide the same type as we currently read
>> out of the scan, but I believe we will have other issues with trying to
>> support this right now as we have not thoroughly tested these other integer
>> types.
>>
>> I would like to instead propose that we change the behavior of Hive to read
>> data of these types into a regular integer columns for now and try to
>> remove any outstanding references to tinyint and smallint until we can
>> commit to fully supporting them.
>>
>> [1] http://drill.apache.org/docs/supported-data-types/
>>
>


-- 
Daniel Barclay
MapR Technologies

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