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

["Julian Hyde (JIRA)" <ji...@apache.org>]

Julian Hyde created CALCITE-771:
-----------------------------------

             Summary: 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
            Assignee: Julian Hyde


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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