Package io.prestosql.sql.planner.iterative.rule

Class EliminateCrossJoins

java.lang.Object

io.prestosql.sql.planner.iterative.rule.EliminateCrossJoins

All Implemented Interfaces:

Rule<JoinNode>

public class EliminateCrossJoins
extends Object
implements Rule<JoinNode>

Nested Class Summary

Nested classes/interfaces inherited from interface io.prestosql.sql.planner.iterative.Rule

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor	Description
EliminateCrossJoins(Metadata metadata)

Method Summary

Modifier and Type	Method	Description
Rule.Result	apply(JoinNode node, Captures captures, Rule.Context context)
static PlanNode	buildJoinTree(List<Symbol> expectedOutputSymbols, JoinGraph graph, List<Integer> joinOrder, PlanNodeIdAllocator idAllocator)
static List<Integer>	getJoinOrder(JoinGraph graph)	Given JoinGraph determine the order of joins between graph nodes by traversing JoinGraph.
Pattern<JoinNode>	getPattern()	Returns a pattern to which plan nodes this rule applies.
boolean	isEnabled(Session session)
static boolean	isOriginalOrder(List<Integer> joinOrder)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EliminateCrossJoins

public EliminateCrossJoins(Metadata metadata)

Method Detail

getPattern

public Pattern<JoinNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<JoinNode>

isEnabled

public boolean isEnabled(Session session)

Specified by:

isEnabled in interface Rule<JoinNode>

apply

public Rule.Result apply(JoinNode node,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<JoinNode>

isOriginalOrder

public static boolean isOriginalOrder(List<Integer> joinOrder)

getJoinOrder

public static List<Integer> getJoinOrder(JoinGraph graph)

Given JoinGraph determine the order of joins between graph nodes by traversing JoinGraph. Any graph traversal algorithm could be used here (like BFS or DFS), but we use PriorityQueue to preserve original JoinOrder as mush as it is possible. PriorityQueue returns next nodes to join in order of their occurrence in original Plan.

buildJoinTree

public static PlanNode buildJoinTree(List<Symbol> expectedOutputSymbols,
                                     JoinGraph graph,
                                     List<Integer> joinOrder,
                                     PlanNodeIdAllocator idAllocator)