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Date: Mon, 25 Feb 2013 17:14:17 +0000 (UTC)
From: "Phabricator (JIRA)" <jira@apache.org>
To: hive-dev@hadoop.apache.org
Message-ID: <JIRA.12626790.1357748365038.334278.1361812457916@arcas>
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Subject: [jira] [Updated] (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:all-tabpanel ]

Phabricator updated HIVE-3874:
------------------------------

    Attachment: HIVE-3874.D8871.1.patch

omalley requested code review of "HIVE-3874 [jira] Create a new Optimized Row Columnar file format for Hive".

Reviewers: JIRA

improve some of the comments on WriterImpl

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

TEST PLAN
  EMPTY

REVISION DETAIL
  https://reviews.facebook.net/D8871

AFFECTED FILES
  ql/src/java/org/apache/hadoop/hive/ql/io/orc/WriterImpl.java

MANAGE HERALD RULES
  https://reviews.facebook.net/herald/view/differential/

WHY DID I GET THIS EMAIL?
  https://reviews.facebook.net/herald/transcript/21597/

To: JIRA, omalley

                
> 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.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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