Apache Superset 1.3.2树状图层级显示异常求助

我尝试在Apache Superset 1.3.2的树状图中展示层级查询结果，但图表始终只显示单个点或直线。最初想用来展示PostgreSQL备份工具pgBackRest的信息结构，没成功；后来换成员工与经理的简单层级查询，问题还是一样。下面是我用的查询语句，恳请有树状图使用经验的人士协助排查。

pgBackRest层级查询语句 #

with recursive cte as (
select 1 as level, ds.name, ds.backup_label, ds.backup_prior from (
select data->'name' as name, 
       (jsonb_array_elements(data->'backup')->>'label')::text as backup_label,
       (jsonb_array_elements(data->'backup')->>'prior')::text as backup_prior
from jsonb_array_elements(v2.pgbackrest_info()) as data
) as ds
where ds.backup_prior is null
union all
select c.level + 1 as level, ds2.name, ds2.backup_label, ds2.backup_prior from (
select data->'name' as name, 
       (jsonb_array_elements(data->'backup')->>'label')::text as backup_label,
       (jsonb_array_elements(data->'backup')->>'prior')::text as backup_prior
from jsonb_array_elements(v2.pgbackrest_info()) as data
) as ds2 join cte c on c.backup_label = ds2.backup_prior)
select * from cte;

员工与经理层级查询语句 #

（原语句存在语法问题，已补全递归CTE的定义）

WITH RECURSIVE tree AS (
  SELECT id, name, manager_id, 1 as depth FROM employees
         WHERE id = 2
  UNION
  SELECT e.id, e.name, e.manager_id, t.depth + 1
  FROM employees as e
  JOIN tree t
  ON t.id = e.manager_id
)
SELECT id, name, manager_id, depth FROM tree;

内容的提问来源于stack exchange，提问作者Ezra Levi