Package org.apache.calcite.rel.rules

Class SemiJoinJoinTransposeRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.SemiJoinJoinTransposeRule

public class SemiJoinJoinTransposeRule
extends RelOptRule

Planner rule that pushes a SemiJoin down in a tree past a Join in order to trigger other rules that will convert SemiJoins.

• SemiJoin(LogicalJoin(X, Y), Z) → LogicalJoin(SemiJoin(X, Z), Y)
• SemiJoin(LogicalJoin(X, Y), Z) → LogicalJoin(X, SemiJoin(Y, Z))

Whether this first or second conversion is applied depends on which operands actually participate in the semi-join.

Field Summary

Fields

Modifier and Type	Field	Description
static SemiJoinJoinTransposeRule	INSTANCE

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

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor	Description
SemiJoinJoinTransposeRule(RelBuilderFactory relBuilderFactory)	Creates a SemiJoinJoinTransposeRule.

Method Summary

Modifier and Type	Method	Description
void	onMatch(RelOptRuleCall call)	Receives notification about a rule match.
private void	setJoinAdjustments(int[] adjustments, int nFieldsX, int nFieldsY, int nFieldsZ, int adjustY, int adjustZ)	Sets an array to reflect how much each index corresponding to a field needs to be adjusted.

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

any, convert, convert, convertList, convertOperand, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, operand, operand, operand, operand, operand, operandJ, operandJ, some, toString, unordered

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

INSTANCE

public static final SemiJoinJoinTransposeRule INSTANCE

Constructor Detail

SemiJoinJoinTransposeRule

public SemiJoinJoinTransposeRule(RelBuilderFactory relBuilderFactory)

Creates a SemiJoinJoinTransposeRule.

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)

setJoinAdjustments

private void setJoinAdjustments(int[] adjustments,
                                int nFieldsX,
                                int nFieldsY,
                                int nFieldsZ,
                                int adjustY,
                                int adjustZ)

Sets an array to reflect how much each index corresponding to a field needs to be adjusted. The array corresponds to fields in a 3-way join between (X, Y, and Z). X remains unchanged, but Y and Z need to be adjusted by some fixed amount as determined by the input.

Parameters:

adjustments - array to be filled out

nFieldsX - number of fields in X

nFieldsY - number of fields in Y

nFieldsZ - number of fields in Z

adjustY - the amount to adjust Y by

adjustZ - the amount to adjust Z by