TTL-Expired Vertex being queried in GO

[wey-gu]

reproduce:

CREATE TAG v_post(id INT NOT NULL, user FIXED_STRING(20) NOT NULL, ts TIMESTAMP);
CREATE TAG v_tag(name FIXED_STRING(29) NOT NULL, ts TIMESTAMP) TTL_DURATION = 30, TTL_COL = "ts";
CREATE EDGE e_tag(ts TIMESTAMP);

INSERT VERTEX v_post(id, user, ts) values "p1001":(1001, "user1", now());
INSERT VERTEX v_tag(name, ts) values "test1":("test1", now());
INSERT VERTEX v_tag(name, ts) values "test2":("test2", now());

INSERT EDGE e_tag(ts) values "p1001"->"test1":(now());
INSERT EDGE e_tag(ts) values "p1001"->"test2":(now());

query after data loaded:

(root@nebula) [basketballplayer]> GO FROM "p1001" OVER e_tag YIELD $$.v_tag.name AS name, $$.v_tag.ts AS ts
+---------+------------+
| name    | ts         |
+---------+------------+
| "test1" | 1632469961 |
+---------+------------+
| "test2" | 1632469962 |
+---------+------------+
Got 2 rows (time spent 68854/108054 us)

Fri, 24 Sep 2021 15:53:29 CST

(root@nebula) [basketballplayer]> MATCH (p:v_post)-[e:e_tag]->(t:v_tag) WHERE id(p) == "p1001" return t.name AS name, t.ts AS ts
+---------+------------+
| name    | ts         |
+---------+------------+
| "test1" | 1632469961 |
+---------+------------+
| "test2" | 1632469962 |
+---------+------------+
Got 2 rows (time spent 56766/90173 us)

Fri, 24 Sep 2021 15:53:30 CST

query after e_tag expired

(root@nebula) [basketballplayer]> MATCH (p:v_post)-[e:e_tag]->(t:v_tag) WHERE id(p) == "p1001" return t.name AS name, t.ts AS ts
+------+----+
| name | ts |
+------+----+
+------+----+
Empty set (time spent 71241/104775 us)

Fri, 24 Sep 2021 15:55:36 CST

(root@nebula) [basketballplayer]> GO FROM "p1001" OVER e_tag YIELD $$.v_tag.name AS name, $$.v_tag.ts AS ts
+------+----+
| name | ts |
+------+----+
|      |    |
+------+----+
|      |    |
+------+----+
Got 2 rows (time spent 30674/62919 us) #<---------------------

Fri, 24 Sep 2021 15:55:38 CST

Shouldn't 0 rows to be returned instead of 2?

[wey-gu]

context slack thread by renman

https://nebulagraph.slack.com/archives/CSHN72Z6X/p1632467880001300

[CPWstatic]

This is because of the hanging edges. And the Match / Go have different semantics. You will be more clear by trying this case:

GO FROM "p1001" OVER e_tag YIELD E_TAG._dst, $$.v_tag.name AS name, $$.v_tag.ts AS ts

[CPWstatic]

This is not an easy handled issue.

[critical27]

Fixed in #3535