org.apache.calcite.rel.rules

Class AggregateProjectMergeRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.AggregateProjectMergeRule

public class AggregateProjectMergeRule
extends RelOptRule

Planner rule that recognizes a Aggregate on top of a Project and if possible aggregate through the project or removes the project.

This is only possible when the grouping expressions and arguments to the aggregate functions are field references (i.e. not expressions).

In some cases, this rule has the effect of trimming: the aggregate will use fewer columns than the project did.

Field Summary

Fields

Modifier and Type	Field and Description
static AggregateProjectMergeRule	INSTANCE

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

description, operands

Method Summary

Methods

Modifier and Type	Method and Description
static RelNode	apply(Aggregate aggregate, Project project)
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

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

any, convert, convert, convertList, 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

INSTANCE

public static final AggregateProjectMergeRule INSTANCE

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)

apply

public static RelNode apply(Aggregate aggregate,
            Project project)