org.apache.calcite.rel.rules

Class MultiJoinProjectTransposeRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.JoinProjectTransposeRule

org.apache.calcite.rel.rules.MultiJoinProjectTransposeRule

public class MultiJoinProjectTransposeRule
extends JoinProjectTransposeRule

MultiJoinProjectTransposeRule implements the rule for pulling LogicalProjects that are on top of a MultiJoin and beneath a LogicalJoin so the LogicalProject appears above the LogicalJoin.

In the process of doing so, also save away information about the respective fields that are referenced in the expressions in the LogicalProject we're pulling up, as well as the join condition, in the resultant MultiJoins

For example, if we have the following subselect:

      (select X.x1, Y.y1 from X, Y
          where X.x2 = Y.y2 and X.x3 = 1 and Y.y3 = 2)

The MultiJoin associated with (X, Y) associates x1 with X and y1 with Y. Although x3 and y3 need to be read due to the filters, they are not required after the row scan has completed and therefore are not saved. The join fields, x2 and y2, are also tracked separately.

Note that by only pulling up projects that are on top of MultiJoins, we preserve projections on top of row scans.

See the superclass for details on restrictions regarding which LogicalProjects cannot be pulled.

Field Summary

Fields

Modifier and Type	Field and Description
static MultiJoinProjectTransposeRule	MULTI_BOTH_PROJECT
static MultiJoinProjectTransposeRule	MULTI_LEFT_PROJECT
static MultiJoinProjectTransposeRule	MULTI_RIGHT_PROJECT

Fields inherited from class org.apache.calcite.rel.rules.JoinProjectTransposeRule

BOTH_PROJECT, LEFT_PROJECT, RIGHT_PROJECT

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

description, operands

Constructor Summary

Constructors

Constructor and Description
MultiJoinProjectTransposeRule(RelOptRuleOperand operand, String description)

Method Summary

Methods

Modifier and Type	Method and Description
protected RelNode	getProjectChild(RelOptRuleCall call, LogicalProject project, boolean leftChild)
protected LogicalProject	getRightChild(RelOptRuleCall call)
protected boolean	hasLeftChild(RelOptRuleCall call)
protected boolean	hasRightChild(RelOptRuleCall call)

Methods inherited from class org.apache.calcite.rel.rules.JoinProjectTransposeRule

getProjectChild, onMatch

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

MULTI_BOTH_PROJECT

public static final MultiJoinProjectTransposeRule MULTI_BOTH_PROJECT

MULTI_LEFT_PROJECT

public static final MultiJoinProjectTransposeRule MULTI_LEFT_PROJECT

MULTI_RIGHT_PROJECT

public static final MultiJoinProjectTransposeRule MULTI_RIGHT_PROJECT

Constructor Detail

MultiJoinProjectTransposeRule

public MultiJoinProjectTransposeRule(RelOptRuleOperand operand,
                             String description)

Method Detail

hasLeftChild

protected boolean hasLeftChild(RelOptRuleCall call)

Overrides:

hasLeftChild in class JoinProjectTransposeRule

Parameters:

call - RelOptRuleCall

Returns:

true if the rule was invoked with a left project child

hasRightChild

protected boolean hasRightChild(RelOptRuleCall call)

Overrides:

hasRightChild in class JoinProjectTransposeRule

Parameters:

call - RelOptRuleCall

Returns:

true if the rule was invoked with 2 children

getRightChild

protected LogicalProject getRightChild(RelOptRuleCall call)

Overrides:

getRightChild in class JoinProjectTransposeRule

Parameters:

call - RelOptRuleCall

Returns:

LogicalProject corresponding to the right child

getProjectChild

protected RelNode getProjectChild(RelOptRuleCall call,
                      LogicalProject project,
                      boolean leftChild)