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https://issues.apache.org/jira/browse/HIVE-3874?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HIVE-3874:
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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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