List<Integer> inputChannels = IterableTransformer.on(node.getColumns())
.transform(exchange.channelGetter())
.list();
OperatorFactory operatorFactory = new TableWriterOperatorFactory(context.getNextOperatorId(), recordSink, types, inputChannels, sampleWeightChannel);
Map<Symbol, Input> layout = ImmutableMap.<Symbol, Input>builder()
.put(node.getOutputSymbols().get(0), new Input(0))
.put(node.getOutputSymbols().get(1), new Input(1))
.build();