@Override
public void meet(LeftJoin leftJoin) {
if (leftJoin.getLeftArg().getBindingNames().containsAll(filterVars)) {
leftJoin.getLeftArg().visit(this);
} else {
relocate(filter, leftJoin);
}
}
public long getCardinality(LeftJoin join, BindingSet bindings) {
long card1 = getCardinality(join.getLeftArg(), bindings);
long card2 = getCardinality(join.getRightArg(), bindings);
double sel = 0.5;
return Math.max(card1, (long) (card1 * card2 * sel));
}