@Override
public PhysicalOperation visitExchange(ExchangeNode node, LocalExecutionPlanContext context)
{
List<TupleInfo> tupleInfos = getSourceOperatorTupleInfos(node, context.getTypes());
OperatorFactory operatorFactory = new ExchangeOperatorFactory(context.getNextOperatorId(), node.getId(), exchangeClientSupplier, tupleInfos);
// Fow now, we assume that remote plans always produce one symbol per channel. TODO: remove this assumption
ImmutableMultimap.Builder<Symbol, Input> outputMappings = ImmutableMultimap.builder();
int channel = 0;
for (Symbol symbol : node.getOutputSymbols()) {