[CALCITE-841] Redundant windows when window function arguments are expressions

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.5.0
• Assignee: Julian Hyde
• Reporter: Sean Hsuan-Yi Chu
• Created: 12/Aug/15 00:10
• Updated: 27/Feb/24 22:24
• Resolved: 04/Sep/15 07:46

Description

Firstly of all, this issue happens when HepPlanner is used with ProjectToWindowRule.PROJECT rule.

A query with this pattern:

select fn(col) over w, fn(expr) over w
from ...

will generate two "LogicalWindow" even if we have only an identical window frame.

For example,

select sum(deptno) over(partition by deptno order by sal) as sum1, 
sum(deptno + deptno) over(partition by deptno order by sal) as sum2
from emp

gives:

LogicalProject($0=[$2], $1=[$4])
  LogicalWindow(window#0=[window(partition {1} order by [0] range between UNBOUNDED PRECEDING and CURRENT ROW aggs [SUM($3)])])
    LogicalProject(SAL=[$0], DEPTNO=[$1], $2=[$2], $3=[+($1, $1)])
      LogicalProject(SAL=[$5], DEPTNO=[$7], $2=[$9])
        LogicalWindow(window#0=[window(partition {7} order by [5] range between UNBOUNDED PRECEDING and CURRENT ROW aggs [SUM($7)])])
          LogicalTableScan(table=[[CATALOG, SALES, EMP]])