DongShengHe created CALCITE-7833:
------------------------------------
Summary: MULTI_JOIN_OPTIMIZE_BUSHY may turn an outer join into an
inner join.
Key: CALCITE-7833
URL: https://issues.apache.org/jira/browse/CALCITE-7833
Project: Calcite
Issue Type: Bug
Reporter: DongShengHe
This issue CALCITE-5289 was not fully resolved by [PR
3763|https://github.com/apache/calcite/pull/3763].
The rule uses outerJoinFactors to detect outer joins, but that field does not
reliably indicate whether a join is outer.
Reproduction cases:
1. The {{MultiJoin}} records this through {{{}isFullOuterJoin=true{}}}, while
{{outerJoinFactors}} is null for both inputs. The guard skips its checks, and
the Bushy rule rebuilds the join as {{{}INNER{}}}.
{code:sql}
select * from emp full join dept on emp.deptno = dept.deptno
{code}
The query is incorrectly transformed into the following plan:
{code:java}
LogicalJoin(condition=[=($9, $0)], joinType=[inner])
LogicalTableScan(table=[[CATALOG, SALES, DEPT]])
LogicalTableScan(table=[[CATALOG, SALES, EMP]])
{code}
2. A LEFT JOIN B ON TRUE
The {{ON TRUE}} condition references no factors, so {{outerJoinFactors}} for
{{B}} is empty. The guard treats it as safe to optimize, and the Bushy rule
rebuilds the join as {{INNER}}.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
