JingDas created CALCITE-5894:
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Summary: Add SortRemoveRedundantRule to remove redundant sort
fields if sort fields contains unique key
Key: CALCITE-5894
URL: https://issues.apache.org/jira/browse/CALCITE-5894
Project: Calcite
Issue Type: New Feature
Reporter: JingDas
Assignee: JingDas
In some scene, Sort fields can be reduct, if sort fields contain unique key
For Example
{code:java}
SELECT name, Emp.salary FROM Emp
order by empno, ename{code}
where `empno` is a key, `ename` is redundant since `empno` alone is sufficient
to determine the order of any two records.
So the SQL can be optimized as following:
{code:java}
SELECT name, Emp.salary FROM Emp
order by empno{code}
Sorting is an expensive operation, however. Therefore, it is imperative that
sorting
is optimized to avoid unnecessary sort field.
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