public class SemiJoinRemoveRule extends RelOptRule
SemiJoin
s from a join tree.
It is invoked after attempts have been made to convert a SemiJoin to an indexed scan on a join factor have failed. Namely, if the join factor does not reduce to a single table that can be scanned using an index.
It should only be enabled if all SemiJoins in the plan are advisory; that is, they can be safely dropped without affecting the semantics of the query.
Modifier and Type | Field and Description |
---|---|
static SemiJoinRemoveRule |
INSTANCE |
description, operands, relBuilderFactory
Constructor and Description |
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SemiJoinRemoveRule(RelBuilderFactory relBuilderFactory)
Creates a SemiJoinRemoveRule.
|
Modifier and Type | Method and Description |
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void |
onMatch(RelOptRuleCall call)
Receives notification about a rule match.
|
any, convert, convert, convertList, convertOperand, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, operand, operand, operand, operand, operand, operandJ, operandJ, some, toString, unordered
public static final SemiJoinRemoveRule INSTANCE
public SemiJoinRemoveRule(RelBuilderFactory relBuilderFactory)
public void onMatch(RelOptRuleCall call)
RelOptRule
call.rels
holds the set of relational
expressions which match the operands to the rule;
call.rels[0]
is the root expression.
Typically a rule would check that the nodes are valid matches, creates
a new expression, then calls back RelOptRuleCall.transformTo(org.apache.calcite.rel.RelNode, java.util.Map<org.apache.calcite.rel.RelNode, org.apache.calcite.rel.RelNode>)
to
register the expression.
onMatch
in class RelOptRule
call
- Rule callRelOptRule.matches(RelOptRuleCall)
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