Hi all. Using SQL with blink planner for batch calculations, i see *Reused* nodes in Optimized Execution Plan while making self join operations:
== Optimized Execution Plan == Union(all=[true], union=[id, v, v0, w0$o0]) :- OverAggregate(orderBy=[id DESC], window#0=[ROW_NUMBER(*) AS w0$o0 ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW], select=[id, v, v0, w0$o0])(reuse_id=[2]) : +- Sort(orderBy=[id DESC]) : +- Exchange(distribution=[single]) : +- Calc(select=[id, v, v0]) : +- HashJoin(joinType=[LeftOuterJoin], where=[($f2 = id0)], select=[id, v, $f2, id0, v0], build=[right]) : :- Exchange(distribution=[hash[$f2]]) : : +- Calc(select=[id, v, (id + 1) AS $f2]) : : +- TableSourceScan(table=[[default_catalog, default_database, t1]], fields=[id, v])(reuse_id=[1]) : +- Exchange(distribution=[hash[id]]) : +- *Reused*(reference_id=[1]) +- *Reused*(reference_id=[2]) Question is: do these steps (scans, intermediate calculations) really be calculated once or it is just a print shortcut?
