[jira] [Commented] (CALCITE-771) Use materialization for scan-project-sort query

["Feng Zhu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16869221#comment-16869221 ] 

Feng Zhu commented on CALCITE-771:
----------------------------------

Hi, [~julianhyde], I opened a PR on this feature, do you have time to review?

> Use materialization for scan-project-sort query
> -----------------------------------------------
>
>                 Key: CALCITE-771
>                 URL: https://issues.apache.org/jira/browse/CALCITE-771
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Julian Hyde
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 10m
>  Remaining Estimate: 0h
>
> If a materialization is defined for scan-project-sort over another table, then scan-project and scan-project-sort queries should be able to use it.
> For example, given the following schema (in pseudo-DDL):
> {code}
> CREATE TABLE Emp (empid, deptno, gender);
> CREATE MATERIALIZATION I_Emp_Deptno AS
>   SELECT deptno, empid FROM Emp ORDER BY deptno;
> {code}
> Calcite should rewrite the query
> {code}SELECT deptno FROM Emp ORDER BY deptno{code}
> to
> {code}
> Project(deptno)
>   TableScan(table=[I_Emp_Deptno])
> {code}
> Note that no sort is necessary.
> This rewrite is important for using secondary indexes.



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