org.apache.calcite.rel.rules

Class MultiJoinOptimizeBushyRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.MultiJoinOptimizeBushyRule

public class MultiJoinOptimizeBushyRule
extends RelOptRule

Planner rule that finds an approximately optimal ordering for join operators using a heuristic algorithm.

It is triggered by the pattern LogicalProject (MultiJoin).

It is similar to LoptOptimizeJoinRule. LoptOptimizeJoinRule is only capable of producing left-deep joins; this rule is capable of producing bushy joins.

TODO:

1. Join conditions that touch 1 factor.
2. Join conditions that touch 3 factors.
3. More than 1 join conditions that touch the same pair of factors, e.g. t0.c1 = t1.c1 and t1.c2 = t0.c3

Field Summary

Fields

Modifier and Type	Field and Description
static MultiJoinOptimizeBushyRule	INSTANCE

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

description, operands

Constructor Summary

Constructors

Constructor and Description
MultiJoinOptimizeBushyRule(RelFactories.JoinFactory joinFactory, RelFactories.ProjectFactory projectFactory) Creates an MultiJoinOptimizeBushyRule.

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 MultiJoinOptimizeBushyRule INSTANCE

Constructor Detail

MultiJoinOptimizeBushyRule

public MultiJoinOptimizeBushyRule(RelFactories.JoinFactory joinFactory,
                          RelFactories.ProjectFactory projectFactory)

Creates an MultiJoinOptimizeBushyRule.

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)