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https://issues.apache.org/jira/browse/HIVE-13873?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15528942#comment-15528942
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ASF GitHub Bot commented on HIVE-13873:
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GitHub user winningsix opened a pull request:
https://github.com/apache/hive/pull/105
HIVE-13873 Column pruning for nested fields
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/winningsix/hive HIVE-13873
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/hive/pull/105.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #105
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commit ea462c256f773410c7023dcbfbe365c7cc8200b6
Author: Ferdinand Xu <cheng.a...@intel.com>
Date: 2016-09-28T01:15:51Z
HIVE-13873 Column pruning for nested fields
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> Column pruning for nested fields
> --------------------------------
>
> Key: HIVE-13873
> URL: https://issues.apache.org/jira/browse/HIVE-13873
> Project: Hive
> Issue Type: New Feature
> Components: Logical Optimizer
> Reporter: Xuefu Zhang
> Assignee: Ferdinand Xu
> Attachments: HIVE-13873.wip.patch
>
>
> Some columnar file formats such as Parquet store fields in struct type also
> column by column using encoding described in Google Dramel pager. It's very
> common in big data where data are stored in structs while queries only needs
> a subset of the the fields in the structs. However, presently Hive still
> needs to read the whole struct regardless whether all fields are selected.
> Therefore, pruning unwanted sub-fields in struct or nested fields at file
> reading time would be a big performance boost for such scenarios.
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