if( pref == Prefer.CUSTOM )
throw new RuntimeException( "cannot return custom format" );
final PhysType physType = PhysTypeImpl.of( implementor.getTypeFactory(), table.getRowType(), JavaRowFormat.ARRAY );
TableHolder tableHolder = new TableHolder( physType, tableDef, getPlatformBroker(), planner );
long ordinal = CascadingTapEnumerable.addHolder( tableHolder );
Constructor<CascadingTapEnumerable> constructor = CascadingEnumerableRel.getConstructorFor( CascadingTapEnumerable.class );
BlockStatement block = new BlockBuilder().append( Expressions.new_( constructor, Expressions.constant( ordinal ) ) ).toBlock();
return implementor.result( physType, block );