Class ExtractJoinFilterRule

  extended by org.eigenbase.relopt.RelOptRule
      extended by org.eigenbase.rel.rules.ExtractJoinFilterRule

public final class ExtractJoinFilterRule
extends RelOptRule

Rule to convert an inner join to a filter on top of a cartesian inner join.

One benefit of this transformation is that after it, the join condition can be combined with conditions and expressions above the join. It also makes the FennelCartesianJoinRule applicable.

3 February, 2006
$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/ $

Field Summary
static ExtractJoinFilterRule instance
          The singleton.
Fields inherited from class org.eigenbase.relopt.RelOptRule
ANY, description, operands
Constructor Summary
private ExtractJoinFilterRule()
          Creates an ExtractJoinFilterRule.
Method Summary
 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


public static final ExtractJoinFilterRule instance
The singleton.

Constructor Detail


private ExtractJoinFilterRule()
Creates an ExtractJoinFilterRule.

Method Detail


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: