Remove vertex de-duplication in AgensGraph

agens=# MATCH (a:person) WHERE a.name = 'jhs' RETURN a;
              a
------------------------------
 person[4.517]{"name": "jhs"}
 person[4.518]{"name": "jhs"}
 person[4.519]{"name": "jhs"}
 person[4.520]{"name": "jhs"}
 person[4.521]{"name": "jhs"}
 person[4.522]{"name": "jhs"}
 person[4.523]{"name": "jhs"}
 person[4.524]{"name": "jhs"}
 person[4.525]{"name": "jhs"}
 person[4.526]{"name": "jhs"}
 person[4.527]{"name": "jhs"}
 person[4.528]{"name": "jhs"}
 person[4.529]{"name": "jhs"}
 person[4.530]{"name": "jhs"}
(14 rows)

agens=# MATCH (a:person)-[r]->(b:person) WHERE a.name = 'jhs' RETURN a,r,b;
              a               |              r              |                b
------------------------------+-----------------------------+---------------------------------
 person[4.517]{"name": "jhs"} | knows[11.15][4.517,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.518]{"name": "jhs"} | knows[11.16][4.518,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.519]{"name": "jhs"} | knows[11.17][4.519,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.520]{"name": "jhs"} | knows[11.18][4.520,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.521]{"name": "jhs"} | knows[11.19][4.521,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.522]{"name": "jhs"} | knows[11.20][4.522,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.523]{"name": "jhs"} | knows[11.21][4.523,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.524]{"name": "jhs"} | knows[11.22][4.524,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.525]{"name": "jhs"} | knows[11.23][4.525,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.526]{"name": "jhs"} | knows[11.24][4.526,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.527]{"name": "jhs"} | knows[11.25][4.527,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.528]{"name": "jhs"} | knows[11.26][4.528,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.529]{"name": "jhs"} | knows[11.27][4.529,4.546]{} | person[4.546]{"name": "hsjeon"}
 person[4.530]{"name": "jhs"} | knows[11.28][4.530,4.546]{} | person[4.546]{"name": "hsjeon"}
(14 rows)

(version 2.1.1)
-- Subtracting the where condition will eliminate all duplicates by comparing all the vertices.
MATCH(a:person)
WHERE a.name = 'jhs'
WITH properties(a) as props, count(*) as cnt, min(id(a)::text::"numeric") as min_gid
MATCH(b:person)
WHERE properties(b) = props
AND cnt >= 2
AND id(b) <> min_gid
DETACH DELETE b;

(version 1.3~2.0)
MATCH (a:person)
WHERE a.name = 'jhs'
WITH properties(a) AS props, count(*) AS cnt
MATCH (b:person) WHERE b.name = 'jhs' AND to_jsonb(cnt) >= 2
WITH props, cnt, id(b) AS id LIMIT 1
MATCH (c:person)
WHERE properties(c) = props
AND id(c) <> id
DETACH DELETE c;
GRAPH WRITE (DELETE VERTEX 13, DELETE EDGE 13)