LeftTupleSets leftTuples = dquery.getResultLeftTupleSets();
LeftTuple childLeftTuple = rightTuple.getFirstChild();
switch ( childLeftTuple.getStagedType() ) {
// handle clash with already staged entries
case LeftTuple.INSERT :
leftTuples.removeInsert( childLeftTuple );
break;
case LeftTuple.UPDATE :
leftTuples.removeUpdate( childLeftTuple );
break;
}