org.eigenbase.rel.rules
Class PullUpProjectsAboveJoinRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      org.eigenbase.rel.rules.PullUpProjectsAboveJoinRule

Direct Known Subclasses:

PullUpProjectsOnTopOfMultiJoinRule

public class PullUpProjectsAboveJoinRule
extends RelOptRule

PullUpProjectsAboveJoinRule implements the rule for pulling ProjectRels beneath a JoinRel above the JoinRel. Projections are pulled up if the ProjectRel doesn't originate from a null generating input in an outer join.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/PullUpProjectsAboveJoinRule.java#9 $

Author:

Zelaine Fong

Field Summary

static PullUpProjectsAboveJoinRule	instanceLeftProjectChild
static PullUpProjectsAboveJoinRule	instanceRightProjectChild
static PullUpProjectsAboveJoinRule	instanceTwoProjectChildren

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

PullUpProjectsAboveJoinRule(RelOptRuleOperand operand, String description)

Method Summary

private void	createProjectExprs(ProjectRel projRel, RelNode joinChild, int adjustmentAmount, RexBuilder rexBuilder, RelDataTypeField[] joinChildrenFields, RexNode[] projExprs, String[] fieldNames, int offset) Creates projection expressions corresponding to one of the inputs into the join
protected RelNode	getProjectChild(RelOptRuleCall call, ProjectRel project, boolean leftChild) Returns the child of the project that will be used as input into the new JoinRel once the projects are pulled above the JoinRel.
protected ProjectRel	getRightChild(RelOptRuleCall call)
protected boolean	hasLeftChild(RelOptRuleCall call)
protected boolean	hasRightChild(RelOptRuleCall call)
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

convert, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, mergeTraitsAndConvert, mergeTraitsAndConvert, toString

Methods inherited from class java.lang.Object

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

Field Detail

instanceTwoProjectChildren

public static final PullUpProjectsAboveJoinRule instanceTwoProjectChildren

instanceLeftProjectChild

public static final PullUpProjectsAboveJoinRule instanceLeftProjectChild

instanceRightProjectChild

public static final PullUpProjectsAboveJoinRule instanceRightProjectChild

Constructor Detail

PullUpProjectsAboveJoinRule

public PullUpProjectsAboveJoinRule(RelOptRuleOperand operand,
                                   String description)

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.eigenbase.rel.RelNode) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)

hasLeftChild

protected boolean hasLeftChild(RelOptRuleCall call)

Parameters:

call - RelOptRuleCall

Returns:

true if the rule was invoked with a left project child

hasRightChild

protected boolean hasRightChild(RelOptRuleCall call)

Parameters:

call - RelOptRuleCall

Returns:

true if the rule was invoked with 2 children

getRightChild

protected ProjectRel getRightChild(RelOptRuleCall call)

Parameters:

call - RelOptRuleCall

Returns:

ProjectRel corresponding to the right child

getProjectChild

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

Returns the child of the project that will be used as input into the new JoinRel once the projects are pulled above the JoinRel.

Parameters:

call - RelOptRuleCall

project - project RelNode

leftChild - true if the project corresponds to the left projection

Returns:

child of the project that will be used as input into the new JoinRel once the projects are pulled above the JoinRel

createProjectExprs

private void createProjectExprs(ProjectRel projRel,
                                RelNode joinChild,
                                int adjustmentAmount,
                                RexBuilder rexBuilder,
                                RelDataTypeField[] joinChildrenFields,
                                RexNode[] projExprs,
                                String[] fieldNames,
                                int offset)

Creates projection expressions corresponding to one of the inputs into the join

Parameters:

projRel - the projection input into the join (if it exists)

joinChild - the child of the projection input (if there is a projection); otherwise, this is the join input

adjustmentAmount - the amount the expressions need to be shifted by

rexBuilder - rex builder

joinChildrenFields - concatentation of the fields from the left and right join inputs (once the projections have been removed)

projExprs - array of projection expressions to be created

fieldNames - array of the names of the projection fields

offset - starting index in the arrays to be filled in