org.apache.calcite.rel.rules

Class AggregateExpandDistinctAggregatesRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.AggregateExpandDistinctAggregatesRule

public final class AggregateExpandDistinctAggregatesRule
extends RelOptRule

Planner rule that expands distinct aggregates (such as COUNT(DISTINCT x)) from a LogicalAggregate.

How this is done depends upon the arguments to the function. If all functions have the same argument (e.g. COUNT(DISTINCT x), SUM(DISTINCT x) both have the argument x) then one extra Aggregate is sufficient.

If there are multiple arguments (e.g. COUNT(DISTINCT x), COUNT(DISTINCT y)) the rule creates separate Aggregates and combines using a Join.

Field Summary

Fields

Modifier and Type	Field and Description
static AggregateExpandDistinctAggregatesRule	INSTANCE The default instance of the rule; operates only on logical expressions.

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

description, operands

Constructor Summary

Constructors

Constructor and Description
AggregateExpandDistinctAggregatesRule(Class<? extends LogicalAggregate> clazz, RelFactories.JoinFactory joinFactory)

Method Summary

Methods

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, 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 AggregateExpandDistinctAggregatesRule INSTANCE

The default instance of the rule; operates only on logical expressions.

Constructor Detail

AggregateExpandDistinctAggregatesRule

public AggregateExpandDistinctAggregatesRule(Class<? extends LogicalAggregate> clazz,
                                     RelFactories.JoinFactory joinFactory)

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)