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From "Eugene Koifman (JIRA)" <>
Subject [jira] [Commented] (HIVE-6316) Document support for new types in HCat
Date Tue, 27 May 2014 21:48:03 GMT


Eugene Koifman commented on HIVE-6316:

Null and Throw are the only possible values.  The description of HIVE-5814 has a usage example:
HCatStorer('','', '-onOutOfRangeValue Throw')
{noformat} does NOT need to be documented, it's internal.  This only
applies when using HCat fro Pig, where the user is expected to use 'onOutOfRangeValue in HCatStorer.
 Is not really related to Data Promotion Behavior.

The HCatInputFormat and HCatOutputFormat section need the same update to the "type mapping"
tables as HCatLoader/HCatStorer.  I think it would be easier to just create link from all
4 current tables to a single page that has the whole table in
exactly.  The headers in the table actually indicate a mapping of Hive Type/Value system to
Pig Type/Value system.

Logically speaking there is no such thing as HCatalog type/value system.  HCatalog connects
Hive tables to Pig/Map Reduce.  Pig has it's own type/value system; MR does not as such and
is expected to use (in HCatRecord) the same classes as used in Hive internally.

so the data type mapping is really Hive<->Pig (HCatLoader/Storer) and Hive<->MR
(HCatInput/OutputFormat) which is why it's all summarized in a single table in my document.

> Document support for new types in HCat
> --------------------------------------
>                 Key: HIVE-6316
>                 URL:
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Documentation, HCatalog
>    Affects Versions: 0.13.0
>            Reporter: Eugene Koifman
>            Assignee: Lefty Leverenz
> HIVE-5814 added support for new types in HCat.  The PDF file in that bug explains exactly
how these map to Pig types.  This should be added to the Wiki somewhere (probably here
> In particular it should be highlighted that copying data from Hive TIMESTAMP to Pig DATETIME,
any 'nanos' in the timestamp will be lost.  Also, HCatStorer now takes new parameter which
is described in the PDF doc.

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