org.apache.calcite.rel.rules

Class AggregateExtractProjectRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.AggregateExtractProjectRule

public class AggregateExtractProjectRule
extends RelOptRule

Rule to extract a Project from an Aggregate and push it down towards the input.

What projections can be safely pushed down depends upon which fields the Aggregate uses.

To prevent cycles, this rule will not extract a Project if the Aggregates input is already a Project.

Field Summary

Fields

Modifier and Type	Field and Description
private static com.google.common.base.Predicate<RelNode>	PREDICATE Predicate that prevents matching against an Aggregate whose input is already a Project.

Fields inherited from class org.apache.calcite.plan.RelOptRule

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor and Description
AggregateExtractProjectRule(Class<? extends Aggregate> aggregateClass, Class<? extends RelNode> inputClass, RelBuilderFactory relBuilderFactory) Creates an AggregateExtractProjectRule.
AggregateExtractProjectRule(RelOptRuleOperand operand, RelBuilderFactory builderFactory)

Method Summary

Modifier and Type	Method and Description
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.apache.calcite.plan.RelOptRule

any, convert, convert, convertList, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, operand, operand, operand, operand, operand, some, toString, unordered

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

PREDICATE

private static final com.google.common.base.Predicate<RelNode> PREDICATE

Predicate that prevents matching against an Aggregate whose input is already a Project. This will prevent this rule firing repeatedly.

Constructor Detail

AggregateExtractProjectRule

public AggregateExtractProjectRule(Class<? extends Aggregate> aggregateClass,
                                   Class<? extends RelNode> inputClass,
                                   RelBuilderFactory relBuilderFactory)

Creates an AggregateExtractProjectRule.

Parameters:

relBuilderFactory - Builder for relational expressions

AggregateExtractProjectRule

public AggregateExtractProjectRule(RelOptRuleOperand operand,
                                   RelBuilderFactory builderFactory)

Method Detail

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. At the time that this method is called, 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.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)