[BUG] WCC has different results between num_workers=1 and num_workers>1 on ldbc with project (person->knows->person))

[hanjf12]

Describe the bug
When run with num_workers=1, the result of wcc is every vertex with its oid. And when num_workers>1 result is fine

Environment (please complete the following information):

• GraphScope version:0.19
• OS: ubuntu20.04

To Reproduce

from graphscope.client.session import session
graphscope.set_option(show_log=True) 
graphscope.set_option(log_level='DEBUG')
from graphscope.dataset import load_p2p_network, load_ldbc

sess = session(cluster_type="hosts", num_workers=1)

graph = load_ldbc(sess=sess)
graph = graph.project(vertices={"person": []}, edges={"knows": []})
wcc_context = graphscope.wcc(graph)
wcc_context.to_dataframe(
    selector={"id": "v.id", "cc": "r"}
).sort_values(by="id")

[sighingnow]

WCC only works on undirected graphs. You need

graph = load_ldbc(sess=sess, directed=False)

to make it work as expected.

[sighingnow]

The error message will be improved in #2487

[hanjf12]

WCC only works on undirected graphs. You need

graph = load_ldbc(sess=sess, directed=False)

to make it work as expected.

Thanks!!

[sighingnow]

Closing as answered.