Class FennelBufferCommonRelSubExprRule

  extended by org.eigenbase.relopt.RelOptRule
      extended by org.eigenbase.relopt.CommonRelSubExprRule
          extended by 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.

$Id: //open/dev/farrago/src/net/sf/farrago/fennel/rel/ $
Zelaine Fong

Field Summary
static FennelBufferCommonRelSubExprRule instance
Fields inherited from class org.eigenbase.relopt.RelOptRule
ANY, description, operands
Constructor Summary
          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


public static final FennelBufferCommonRelSubExprRule instance
Constructor Detail


public FennelBufferCommonRelSubExprRule()
Deprecated. use instance instead

Method Detail


public CallingConvention getOutConvention()
Description copied from class: RelOptRule
Returns the calling convention of the result of firing this rule, null if not known.

getOutConvention in class RelOptRule


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
call - Rule call
See Also: