JingDas created CALCITE-5928:
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Summary: Add SortHomogenizeRule for homogenization sort fields for
futher optimize
Key: CALCITE-5928
URL: https://issues.apache.org/jira/browse/CALCITE-5928
Project: Calcite
Issue Type: New Feature
Reporter: JingDas
Assignee: JingDas
When an interesting order is pushed down, some columns may have to be
substituted with equivalent columns in the new context. This is referred to as
homogenuzatzon.
For example, consider the following query:
{code:java}
select * from sales.emp e
left join (
select * from sales.dept d) d on e.deptno = d.deptno
order by e.sal, d.deptno{code}
The filed `e.sal`, `d.deptno` will not push down through join, because d.deptno
is unavalilable until after the join.
We can homogenize the sort fields from `e.sal`, `d.deptno` to `e.sal`,
`e.deptno` since
e.deptno = d.deptno. Then sort fields can be pushed down by
`SortJoinTransposeRule`
The theoretical basis comes from paper [Fundamental Techniques for Order
Optimization|https://dl.acm.org/doi/pdf/10.1145/233269.233320]
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