presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/metadata/Distribution.java/Distribution/serializeColumnTypes
class Distribution:    public static String serializeColumnTypes(List<Type> columnTypes)
    {
        return LIST_CODEC.toJson(columnTypes.stream()
                .map(type -> type.getTypeId().getId())
                .collect(toList()));
    }