org.eigenbase.rel.rules
Class PushFilterPastJoinRule

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

public class PushFilterPastJoinRule
extends RelOptRule

PushFilterPastJoinRule implements the rule for pushing filters above and within a join node into the join node and/or its children nodes.

Version:

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/PushFilterPastJoinRule.java#14 $

Author:

Zelaine Fong

Field Summary

static PushFilterPastJoinRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

private	PushFilterPastJoinRule() Creates a PushFilterPastJoinRule.
	PushFilterPastJoinRule(RelOptRuleOperand operand, String id) Creates a PushFilterPastJoinRule with an explicit root operand.

Method Summary

private RelNode	createFilterOnRel(RexBuilder rexBuilder, RelNode rel, List<RexNode> filters) If the filter list passed in is non-empty, creates a FilterRel on top of the existing RelNode; otherwise, just returns the RelNode
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

instance

public static final PushFilterPastJoinRule instance

Constructor Detail

PushFilterPastJoinRule

private PushFilterPastJoinRule()

Creates a PushFilterPastJoinRule.

PushFilterPastJoinRule

public PushFilterPastJoinRule(RelOptRuleOperand operand,
                              String id)

Creates a PushFilterPastJoinRule with an explicit root operand.

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)

createFilterOnRel

private RelNode createFilterOnRel(RexBuilder rexBuilder,
                                  RelNode rel,
                                  List<RexNode> filters)

If the filter list passed in is non-empty, creates a FilterRel on top of the existing RelNode; otherwise, just returns the RelNode

Parameters:

rexBuilder - rex builder

rel - the RelNode that the filter will be put on top of

filters - list of filters

Returns:

new RelNode or existing one if no filters