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https://issues.apache.org/jira/browse/DRILL-491?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jinfeng Ni updated DRILL-491:
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Attachment: DRILL-491.3.patch
The patch contains the following change:
1. Revise code based on review comments.
2. Add method clone() to GroupScan interface. This will save the time spent on
initializing groupscan instance, when optiq rules are fired multiple times.
3. Add a base class for plan testing. The base class will be used for
verifying either logical / physical plan produced by optimizer.
4. Add more test to test project pushdown : use INFORMATION_SCHEMA (for
schema-based query), and TPCH similar queries.
> 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-491.3.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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