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

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	MultiJoinOptimizeBushyRule.JoinVertex Participant in a join which is itself a join.
(package private) static class	MultiJoinOptimizeBushyRule.LeafVertex Relation participating in a join.
(package private) static class	MultiJoinOptimizeBushyRule.Vertex Participant in a join (relation or join).

Field Summary

Fields

Modifier and Type	Field and Description
static MultiJoinOptimizeBushyRule	INSTANCE
private PrintWriter	pw

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

description, operands, relBuilderFactory

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
(package private) int	chooseBestEdge(List<LoptMultiJoin.Edge> edges, Comparator<LoptMultiJoin.Edge> comparator)
(package private) static <E> int	minPos(List<E> list, Comparator<E> fn) Returns the index within a list at which compares least according to a comparator.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.
private void	trace(List<MultiJoinOptimizeBushyRule.Vertex> vertexes, List<LoptMultiJoin.Edge> unusedEdges, List<LoptMultiJoin.Edge> usedEdges, int edgeOrdinal, PrintWriter pw)

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

INSTANCE

public static final MultiJoinOptimizeBushyRule INSTANCE

pw

private final PrintWriter pw

Constructor Detail

MultiJoinOptimizeBushyRule

public MultiJoinOptimizeBushyRule(RelBuilderFactory relBuilderFactory)

Creates an MultiJoinOptimizeBushyRule.

MultiJoinOptimizeBushyRule

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

Deprecated.

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)

trace

private void trace(List<MultiJoinOptimizeBushyRule.Vertex> vertexes,
                   List<LoptMultiJoin.Edge> unusedEdges,
                   List<LoptMultiJoin.Edge> usedEdges,
                   int edgeOrdinal,
                   PrintWriter pw)

chooseBestEdge

int chooseBestEdge(List<LoptMultiJoin.Edge> edges,
                   Comparator<LoptMultiJoin.Edge> comparator)

minPos

static <E> int minPos(List<E> list,
                      Comparator<E> fn)

Returns the index within a list at which compares least according to a comparator.

In the case of a tie, returns the earliest such element.

If the list is empty, returns -1.