presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/metadata/BucketNode.java/BucketNode/map
class BucketNode:        @Override
        public BucketNode map(int index, ResultSet rs, StatementContext context)
                throws SQLException
        {
            return new BucketNode(
                    rs.getInt("bucket_number"),
                    rs.getString("node_identifier"));
        }