`DISTINCT` collision when string values contain commas

[ting668]

Reporter: ting668

Environment

• OS: CentOS Linux 7 (Core), inside Docker container
• CPU/Architecture: x86_64
• Docker image: tugraph/tugraph-runtime-centos7:latest
• TuGraph-DB Version: 4.5.2 (tugraph-4.5.2-1.x86_64)

Description

While testing TuGraph using a method based on attribute-constraint analysis, I found that DISTINCT can merge different rows when string values contain commas.

Different tuples appear to be serialized into the same internal distinct key.

How to Reproduce and Expected Behavior

Example query:

UNWIND [{x:'a,b', y:'c'}, {x:'a', y:'b,c'}] AS row
RETURN DISTINCT row.x AS x, row.y AS y;

Expected behavior: TuGraph should return 2 rows:

('a,b', 'c')
('a', 'b,c')

Actual behavior: TuGraph returns only 1 row:

('a,b', 'c')

The two different tuples appear to collide because both can be represented as the comma-joined string a,b,c.