org.apache.calcite.rel.core

Class Join

java.lang.Object

org.apache.calcite.rel.AbstractRelNode

org.apache.calcite.rel.BiRel

org.apache.calcite.rel.core.Join

All Implemented Interfaces:

Cloneable, RelOptNode, RelNode

Direct Known Subclasses:

Bindables.BindableJoin, EnumerableThetaJoin, EquiJoin, JdbcRules.JdbcJoin, LogicalJoin

public abstract class Join
extends BiRel

Relational expression that combines two relational expressions according to some condition.

Each output row has columns from the left and right inputs. The set of output rows is a subset of the cartesian product of the two inputs; precisely which subset depends on the join condition.

Field Summary

Fields

Modifier and Type	Field and Description
protected RexNode	condition
protected JoinRelType	joinType Values must be of enumeration JoinRelType, except that JoinRelType.RIGHT is disallowed.
protected com.google.common.collect.ImmutableSet<String>	variablesStopped

Fields inherited from class org.apache.calcite.rel.BiRel

left, right

Fields inherited from class org.apache.calcite.rel.AbstractRelNode

digest, id, rowType, traitSet

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Join(RelOptCluster cluster, RelTraitSet traits, RelNode left, RelNode right, RexNode condition, JoinRelType joinType, Set<String> variablesStopped) Creates a Join.

Method Summary

Methods

Modifier and Type	Method and Description
RelNode	accept(RexShuttle shuttle) Accepts a visit from a shuttle.
JoinInfo	analyzeCondition() Analyzes the join condition.
RelOptCost	computeSelfCost(RelOptPlanner planner) Returns the cost of this plan (not including children).
Join	copy(RelTraitSet traitSet, List<RelNode> inputs) Creates a copy of this relational expression, perhaps changing traits and inputs.
abstract Join	copy(RelTraitSet traitSet, RexNode conditionExpr, RelNode left, RelNode right, JoinRelType joinType, boolean semiJoinDone) Creates a copy of this join, overriding condition, system fields and inputs.
static RelDataType	createJoinType(RelDataTypeFactory typeFactory, RelDataType leftType, RelDataType rightType, List<String> fieldNameList, List<RelDataTypeField> systemFieldList) Returns the type the row which results when two relations are joined.
static RelDataType	deriveJoinRowType(RelDataType leftType, RelDataType rightType, JoinRelType joinType, RelDataTypeFactory typeFactory, List<String> fieldNameList, List<RelDataTypeField> systemFieldList) Derives the type of a join relational expression.
protected RelDataType	deriveRowType()
static double	estimateJoinedRows(Join joinRel, RexNode condition)
RelWriter	explainTerms(RelWriter pw) Describes the inputs and attributes of this relational expression.
List<RexNode>	getChildExps() Returns a list of this relational expression's child expressions.
RexNode	getCondition()
JoinRelType	getJoinType()
double	getRows() Returns an estimate of the number of rows this relational expression will return.
List<RelDataTypeField>	getSystemFieldList() Returns a list of system fields that will be prefixed to output row type.
Set<String>	getVariablesStopped() Returns the names of variables which are set in this relational expression but also used and therefore not available to parents of this relational expression.
boolean	isSemiJoinDone() Returns whether this LogicalJoin has already spawned a SemiJoin via JoinAddRedundantSemiJoinRule.
boolean	isValid_(boolean fail)

Methods inherited from class org.apache.calcite.rel.BiRel

childrenAccept, getInputs, getLeft, getRight, replaceInput

Methods inherited from class org.apache.calcite.rel.AbstractRelNode

accept, collectVariablesSet, collectVariablesUsed, computeDigest, explain, getCluster, getCollationList, getConvention, getCorrelVariable, getDescription, getDigest, getExpectedInputRowType, getId, getInput, getQuery, getRelTypeName, getRowType, getTable, getTraitSet, isDistinct, isKey, isValid, metadata, onRegister, recomputeDigest, register, sole, toString

Methods inherited from class java.lang.Object

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

Field Detail

condition

protected final RexNode condition

variablesStopped

protected final com.google.common.collect.ImmutableSet<String> variablesStopped

joinType

protected JoinRelType joinType

Values must be of enumeration JoinRelType, except that JoinRelType.RIGHT is disallowed.

Constructor Detail

Join

protected Join(RelOptCluster cluster,
    RelTraitSet traits,
    RelNode left,
    RelNode right,
    RexNode condition,
    JoinRelType joinType,
    Set<String> variablesStopped)

Creates a Join.

Parameters:

cluster - Cluster

traits - Traits

left - Left input

right - Right input

condition - Join condition

joinType - Join type

variablesStopped - Set of names of variables which are set by the LHS and used by the RHS and are not available to nodes above this LogicalJoin in the tree

Method Detail

getChildExps

public List<RexNode> getChildExps()

Description copied from interface: RelNode

Returns a list of this relational expression's child expressions. (These are scalar expressions, and so do not include the relational inputs that are returned by RelNode.getInputs().

The caller should treat the list as unmodifiable; typical implementations will return an immutable list. If there are no child expressions, returns an empty list, not null.

Specified by:

getChildExps in interface RelNode

Overrides:

getChildExps in class AbstractRelNode

Returns:

List of this relational expression's child expressions

See Also:

RelNode.accept(org.apache.calcite.rex.RexShuttle)

accept

public RelNode accept(RexShuttle shuttle)

Description copied from interface: RelNode

Accepts a visit from a shuttle. If the shuttle updates expression, then a copy of the relation should be created.

Specified by:

accept in interface RelNode

Overrides:

accept in class AbstractRelNode

Parameters:

shuttle - Shuttle

Returns:

A copy of this node incorporating changes made by the shuttle to this node's children

getCondition

public RexNode getCondition()

getJoinType

public JoinRelType getJoinType()

isValid_

public boolean isValid_(boolean fail)

computeSelfCost

public RelOptCost computeSelfCost(RelOptPlanner planner)

Description copied from interface: RelNode

Returns the cost of this plan (not including children). The base implementation throws an error; derived classes should override.

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getNonCumulativeCost(org.apache.calcite.rel.RelNode), which gives plugins a chance to override the rel's default ideas about cost.

Specified by:

computeSelfCost in interface RelNode

Overrides:

computeSelfCost in class AbstractRelNode

Parameters:

planner - Planner for cost calculation

Returns:

Cost of this plan (not including children)

estimateJoinedRows

public static double estimateJoinedRows(Join joinRel,
                        RexNode condition)

getRows

public double getRows()

Description copied from interface: RelNode

Returns an estimate of the number of rows this relational expression will return.

NOTE jvs 29-Mar-2006: Don't call this method directly. Instead, use RelMetadataQuery.getRowCount(org.apache.calcite.rel.RelNode), which gives plugins a chance to override the rel's default ideas about row count.

Specified by:

getRows in interface RelNode

Overrides:

getRows in class AbstractRelNode

Returns:

Estimate of the number of rows this relational expression will return

getVariablesStopped

public Set<String> getVariablesStopped()

Description copied from interface: RelNode

Returns the names of variables which are set in this relational expression but also used and therefore not available to parents of this relational expression.

Note: only Correlate should set variables

Specified by:

getVariablesStopped in interface RelNode

Overrides:

getVariablesStopped in class AbstractRelNode

Returns:

Names of variables which are set in this relational expression

explainTerms

public RelWriter explainTerms(RelWriter pw)

Description copied from class: AbstractRelNode

Describes the inputs and attributes of this relational expression. Each node should call super.explainTerms, then call the RelWriterImpl.input(String, RelNode) and RelWriterImpl.item(String, Object) methods for each input and attribute.

Overrides:

explainTerms in class BiRel

Parameters:

pw - Plan writer

Returns:

Plan writer for fluent-explain pattern

deriveRowType

protected RelDataType deriveRowType()

Overrides:

deriveRowType in class AbstractRelNode

isSemiJoinDone

public boolean isSemiJoinDone()

Returns whether this LogicalJoin has already spawned a SemiJoin via JoinAddRedundantSemiJoinRule.

The base implementation returns false.

Returns:

whether this join has already spawned a semi join

getSystemFieldList

public List<RelDataTypeField> getSystemFieldList()

Returns a list of system fields that will be prefixed to output row type.

Returns:

list of system fields

deriveJoinRowType

public static RelDataType deriveJoinRowType(RelDataType leftType,
                            RelDataType rightType,
                            JoinRelType joinType,
                            RelDataTypeFactory typeFactory,
                            List<String> fieldNameList,
                            List<RelDataTypeField> systemFieldList)

Derives the type of a join relational expression.

Parameters:

leftType - Row type of left input to join

rightType - Row type of right input to join

joinType - Type of join

typeFactory - Type factory

fieldNameList - List of names of fields; if null, field names are inherited and made unique

systemFieldList - List of system fields that will be prefixed to output row type; typically empty but must not be null

Returns:

join type

createJoinType

public static RelDataType createJoinType(RelDataTypeFactory typeFactory,
                         RelDataType leftType,
                         RelDataType rightType,
                         List<String> fieldNameList,
                         List<RelDataTypeField> systemFieldList)

Returns the type the row which results when two relations are joined.

The resulting row type consists of the system fields (if any), followed by the fields of the left type, followed by the fields of the right type. The field name list, if present, overrides the original names of the fields.

Parameters:

typeFactory - Type factory

leftType - Type of left input to join

rightType - Type of right input to join

fieldNameList - If not null, overrides the original names of the fields

systemFieldList - List of system fields that will be prefixed to output row type; typically empty but must not be null

Returns:

type of row which results when two relations are joined

copy

public final Join copy(RelTraitSet traitSet,
        List<RelNode> inputs)

Description copied from interface: RelNode

Creates a copy of this relational expression, perhaps changing traits and inputs.

Sub-classes with other important attributes are encouraged to create variants of this method with more parameters.

Specified by:

copy in interface RelNode

Overrides:

copy in class AbstractRelNode

Parameters:

traitSet - Trait set

inputs - Inputs

Returns:

Copy of this relational expression, substituting traits and inputs

copy

public abstract Join copy(RelTraitSet traitSet,
        RexNode conditionExpr,
        RelNode left,
        RelNode right,
        JoinRelType joinType,
        boolean semiJoinDone)

Creates a copy of this join, overriding condition, system fields and inputs.

General contract as RelNode.copy(org.apache.calcite.plan.RelTraitSet, java.util.List<org.apache.calcite.rel.RelNode>).

Parameters:

traitSet - Traits

conditionExpr - Condition

left - Left input

right - Right input

joinType - Join type

semiJoinDone - Whether this join has been translated to a semi-join

Returns:

Copy of this join

analyzeCondition

public JoinInfo analyzeCondition()

Analyzes the join condition.

Returns:

Analyzed join condition