Class PushSemiJoinPastFilterRule

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

public class PushSemiJoinPastFilterRule
extends RelOptRule

PushSemiJoinPastFilterRule implements the rule for pushing semijoins down in a tree past a filter in order to trigger other rules that will convert semijoins. SemiJoinRel(FilterRel(X), Y) --> FilterRel(SemiJoinRel(X, Y))

$Id: //open/dev/farrago/src/org/eigenbase/rel/rules/ $
Zelaine Fong

Field Summary
static PushSemiJoinPastFilterRule instance
Fields inherited from class org.eigenbase.relopt.RelOptRule
ANY, description, operands
Constructor Summary
private PushSemiJoinPastFilterRule()
          Creates a PushSemiJoinPastFilterRule.
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 PushSemiJoinPastFilterRule instance
Constructor Detail


private PushSemiJoinPastFilterRule()
Creates a PushSemiJoinPastFilterRule.

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: