presto-main/src/main/java/io/prestosql/sql/planner/optimizations/StreamPropertyDerivations.java/Visitor/visitAssignUniqueId
class Visitor:        @Override
        public StreamProperties visitAssignUniqueId(AssignUniqueId node, List<StreamProperties> inputProperties)
        {
            StreamProperties properties = Iterables.getOnlyElement(inputProperties);
            if (properties.getPartitioningColumns().isPresent()) {
                // preserve input (possibly preferred) partitioning
                return properties;
            }

            return new StreamProperties(properties.getDistribution(),
                    Optional.of(ImmutableList.of(node.getIdColumn())),
                    properties.isOrdered());
        }