GitHub user xuanyuanking opened a pull request:
https://github.com/apache/spark/pull/21839
[SPARK-24339][SQL] Prunes the unused columns from child of
ScriptTransformation
## What changes were proposed in this pull request?
Modify the strategy in ColumnPruning to add a Project between
ScriptTransformation and its child, this strategy can reduce the scan time
especially in the scenario of the table has many columns.
## How was this patch tested?
Add UT in ColumnPruningSuite.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/xuanyuanking/spark SPARK-24339
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/21839.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 #21839
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commit 68869d9fb8cc0e2686fb1e01f4d4c3e7ac8a52fe
Author: Yuanjian Li <xyliyuanjian@...>
Date: 2018-07-22T14:46:31Z
Prunes the unused columns from child of ScriptTransformation
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