net.sf.farrago.fennel.rel
Class FennelBufferCommonRelSubExprRule

java.lang.Object
  org.eigenbase.relopt.RelOptRule
      org.eigenbase.relopt.CommonRelSubExprRule
          net.sf.farrago.fennel.rel.FennelBufferCommonRelSubExprRule

public class FennelBufferCommonRelSubExprRule
extends CommonRelSubExprRule

FennelBufferCommonRelSubExprRule is a rule that places a Fennel buffering node on top of a common relational subexpression, provided it makes sense to do so from a cost perspective.

Version:

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/FennelBufferCommonRelSubExprRule.java#1 $

Author:

Zelaine Fong

Field Summary

static FennelBufferCommonRelSubExprRule

instance

Fields inherited from class org.eigenbase.relopt.RelOptRule

ANY, description, operands

Constructor Summary

FennelBufferCommonRelSubExprRule()
Deprecated. use instance instead

Method Summary

CallingConvention	getOutConvention() Returns the calling convention of the result of firing this rule, null if not known.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.eigenbase.relopt.RelOptRule

convert, equals, equals, getOperand, getOperands, 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 FennelBufferCommonRelSubExprRule instance

Constructor Detail

FennelBufferCommonRelSubExprRule

public FennelBufferCommonRelSubExprRule()

Deprecated. use instance instead

Method Detail

getOutConvention

public CallingConvention getOutConvention()

Description copied from class: RelOptRule

Returns the calling convention of the result of firing this rule, null if not known.

Overrides:

getOutConvention in class RelOptRule

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)