com.lucidera.opt
Class LoptModifyRemovableSelfJoinRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      com.lucidera.opt.LoptModifyRemovableSelfJoinRule

public class LoptModifyRemovableSelfJoinRule
extends RelOptRule

LoptModifyRemovableSelfJoinRule implements a rule that modifies the inputs into a removable self-join so that they are in a standard format that will be recognized by LoptRemoveSelfJoinRule.

Each input into the join is already a simple LcsRowScanRel. There needs to be a FilterRel and ProjectRel on top of each of the row scans. So, this rule adds the missing ProjectRel and/or FilterRel. The FilterRel contains a dummy IS TRUE expression while the ProjectRel simply projects each column. Both will be removed later by LoptRemoveSelfJoinRule.

Version:

$Id: //open/dev/farrago/src/com/lucidera/opt/LoptModifyRemovableSelfJoinRule.java#5 $

Author:

Zelaine Fong

Field Summary

static LoptModifyRemovableSelfJoinRule	instanceFilterOnLeft
static LoptModifyRemovableSelfJoinRule	instanceFilterOnRight
static LoptModifyRemovableSelfJoinRule	instanceProjectOnLeft
static LoptModifyRemovableSelfJoinRule	instanceProjectOnRight
static LoptModifyRemovableSelfJoinRule	instanceRowScanOnLeft
static LoptModifyRemovableSelfJoinRule	instanceRowScanOnRight

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

LoptModifyRemovableSelfJoinRule(RelOptRuleOperand operand, String id)
Creates a LoptModifyRemovableSelfJoinRule.

Method Summary

private ProjectRel	addFilter(ProjectRel projRel) Inserts a FilterRel with a TRUE condition in between a ProjectRel and its input.
private ProjectRel	addProject(RelNode filterRel) Inserts a ProjectRel on top of a filter node.
private ProjectRel	addProjectAndFilter(RelNode rowScan) Inserts a ProjectRel and FilterRel on top of a row scan.
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

instanceRowScanOnLeft

public static final LoptModifyRemovableSelfJoinRule instanceRowScanOnLeft

instanceRowScanOnRight

public static final LoptModifyRemovableSelfJoinRule instanceRowScanOnRight

instanceFilterOnLeft

public static final LoptModifyRemovableSelfJoinRule instanceFilterOnLeft

instanceProjectOnLeft

public static final LoptModifyRemovableSelfJoinRule instanceProjectOnLeft

instanceFilterOnRight

public static final LoptModifyRemovableSelfJoinRule instanceFilterOnRight

instanceProjectOnRight

public static final LoptModifyRemovableSelfJoinRule instanceProjectOnRight

Constructor Detail

LoptModifyRemovableSelfJoinRule

public LoptModifyRemovableSelfJoinRule(RelOptRuleOperand operand,
                                       String id)

Creates a LoptModifyRemovableSelfJoinRule.

Parameters:

operand - Root operand, must not be null

id - Description of rule

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)

addProjectAndFilter

private ProjectRel addProjectAndFilter(RelNode rowScan)

Inserts a ProjectRel and FilterRel on top of a row scan.

Parameters:

rowScan - the row scan

Returns:

the constructed RelNode tree

addProject

private ProjectRel addProject(RelNode filterRel)

Inserts a ProjectRel on top of a filter node.

Parameters:

filterRel - the filter node

Returns:

the constructed ProjectRel tree

addFilter

private ProjectRel addFilter(ProjectRel projRel)

Inserts a FilterRel with a TRUE condition in between a ProjectRel and its input.

Parameters:

projRel - the ProjectRel

Returns:

the constructed RelNode tree