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Posted to dev@drill.apache.org by "Jacques Nadeau (JIRA)" <ji...@apache.org> on 2014/04/20 03:27:15 UTC
[jira] [Commented] (DRILL-491) Support project push-down into scan
operator
[ https://issues.apache.org/jira/browse/DRILL-491?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13975007#comment-13975007 ]
Jacques Nadeau commented on DRILL-491:
--------------------------------------
please update patch for latest master
> Support project push-down into scan operator
> --------------------------------------------
>
> Key: DRILL-491
> URL: https://issues.apache.org/jira/browse/DRILL-491
> Project: Apache Drill
> Issue Type: Bug
> Reporter: Jinfeng Ni
> Assignee: Jinfeng Ni
> Attachments: DRILL-491.1.patch
>
>
> Currently, the scan operator will read all the columns from the data source, and pass all the columns to down-stream operator.
> In order to improve performance of Drill query, we should instead push the project operation into scan operator. The scan operator will take as an input a list of columns required to retrieve. If the query only refers a subset of columns, the scan operator will only have to retrieve values for the column in the list.
> It's expected to see performance improvement once project push-down is supported.
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