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Date: Fri, 11 Jan 2013 18:22:13 +0000 (UTC)
From: "Namit Jain (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: <JIRA.12626790.1357748365038.121383.1357928533037@arcas>
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Subject: [jira] [Commented] (HIVE-3874) Create a new Optimized Row Columnar
 file format for Hive
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    [ https://issues.apache.org/jira/browse/HIVE-3874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13551347#comment-13551347 ] 

Namit Jain commented on HIVE-3874:
----------------------------------

Owen, that would be good 'a table property like 'orc.create.index' or something'
                
> Create a new Optimized Row Columnar file format for Hive
> --------------------------------------------------------
>
>                 Key: HIVE-3874
>                 URL: https://issues.apache.org/jira/browse/HIVE-3874
>             Project: Hive
>          Issue Type: Improvement
>          Components: Serializers/Deserializers
>            Reporter: Owen O'Malley
>            Assignee: Owen O'Malley
>         Attachments: OrcFileIntro.pptx
>
>
> There are several limitations of the current RC File format that I'd like to address by creating a new format:
> * each column value is stored as a binary blob, which means:
> ** the entire column value must be read, decompressed, and deserialized
> ** the file format can't use smarter type-specific compression
> ** push down filters can't be evaluated
> * the start of each row group needs to be found by scanning
> * user metadata can only be added to the file when the file is created
> * the file doesn't store the number of rows per a file or row group
> * there is no mechanism for seeking to a particular row number, which is required for external indexes.
> * there is no mechanism for storing light weight indexes within the file to enable push-down filters to skip entire row groups.
> * the type of the rows aren't stored in the file

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