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Posted to dev@hive.apache.org by "Pamela Vagata (JIRA)" <ji...@apache.org> on 2013/03/01 01:17:16 UTC
[jira] [Commented] (HIVE-3874) Create a new Optimized Row Columnar
file format for Hive
[ https://issues.apache.org/jira/browse/HIVE-3874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13590092#comment-13590092 ]
Pamela Vagata commented on HIVE-3874:
-------------------------------------
Owen, would you mind filing the bug as a separate JIRA and committing the code as is? We are currently hunting down issues and putting together fixes :)
> 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: hive.3874.2.patch, HIVE-3874.D8529.1.patch, HIVE-3874.D8529.2.patch, HIVE-3874.D8529.3.patch, HIVE-3874.D8529.4.patch, HIVE-3874.D8871.1.patch, OrcFileIntro.pptx, orc.tgz
>
>
> 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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