James Starr created CALCITE-4668:
------------------------------------
Summary: RelBuilder.join should only emit a correlate when a
correlate variable exists
Key: CALCITE-4668
URL: https://issues.apache.org/jira/browse/CALCITE-4668
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: James Starr
We generate correlated join when no correlate variable is present on the right
side. However, this could be simplified to emit a normal join.
Given:
{code:java}
final RelNode rel = builder
.scan("EMP")
.variable(v)
.scan("DEPT")
.join(JoinRelType.LEFT,
builder.equals(builder.field(2, 0, "SAL"),
builder.literal(1000)),
ImmutableSet.of(v.get().id))
.build();
{code}
Currently the following is emitted:
{code}
LogicalFilter(condition=[=($7, $8)])
LogicalCorrelate(correlation=[$cor0], joinType=[left], requiredColumns=[{0}])
LogicalTableScan(table=[[scott, EMP]])
LogicalFilter(condition=[=($cor0.DEPTNO, $0)])
LogicalTableScan(table=[[scott, DEPT]])
{code}
After the changes the following will be emitted:
{code}
LogicalJoin(condition=[=($7, $8)], joinType=[left])
LogicalTableScan(table=[[scott, EMP]])
LogicalTableScan(table=[[scott, DEPT]])
{code}
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
