Cypher: Returned edges (serialised) are not filtered by query

[artturimatias]

ArcadeDB Version: 22.11.1

JDK Version: Docker image

OS:Linux

Expected behavior

Query with edge type should return only those edges:

MATCH (p:Person)-[:IS_COORDINATOR_OF]->(pr:Project) RETURN p, pr

Actual behavior

Returned set (serialised with 'graph' option) includes all edges between selected nodes.

Steps to reproduce

Create a simple graph, two persons and two projects.

CREATE (p:Person {name: "Bob"})-[:IS_COORDINATOR_OF]->(pr:Project {name: "Bob's Project"}) RETURN p, pr

CREATE (p:Person {name: "Jenny"})-[:IS_COORDINATOR_OF]->(pr:Project {name: "Jenny's Project"}) RETURN p, pr

MATCH (p:Person {name: "Bob"}), (pr:Project {name:"Jenny's Project"}) CREATE (p)-[:IS_MEMBER_OF]->(pr) return p,pr

MATCH (p:Person {name: "Jenny"}), (pr:Project {name:"Bob's Project"}) CREATE (p)-[:IS_MEMBER_OF]->(pr) return p,pr

Then try to get project coordinators:

MATCH (p:Person)-[:IS_COORDINATOR_OF]->(pr:Project) RETURN p, pr

    {
  "result": {
    "vertices": [
      {
        "p": {
          "name": "Bob"
        },
        "r": "#10:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Bob's Project"
        },
        "r": "#28:0",
        "t": "Project",
        "i": 2,
        "o": 0
      },
      {
        "p": {
          "name": "Jenny"
        },
        "r": "#13:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Jenny's Project"
        },
        "r": "#31:0",
        "t": "Project",
        "i": 2,
        "o": 0
      }
    ],
    "records": [
      {
        "p": {
          "@rid": "#10:0",
          "@type": "Person",
          "name": "Bob"
        },
        "pr": {
          "@rid": "#28:0",
          "@type": "Project",
          "name": "Bob's Project"
        }
      },
      {
        "p": {
          "@rid": "#13:0",
          "@type": "Person",
          "name": "Jenny"
        },
        "pr": {
          "@rid": "#31:0",
          "@type": "Project",
          "name": "Jenny's Project"
        }
      }
    ],
    "edges": [
      {
        "p": {},
        "r": "#51:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#31:0",
        "o": "#13:0"
      },
      {
        "p": {},
        "r": "#57:0",
        "t": "IS_MEMBER_OF",
        "i": "#31:0",
        "o": "#10:0"
      },
      {
        "p": {},
        "r": "#50:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#28:0",
        "o": "#10:0"
      },
      {
        "p": {},
        "r": "#57:0",
        "t": "IS_MEMBER_OF",
        "i": "#31:0",
        "o": "#10:0"
      },
      {
        "p": {},
        "r": "#50:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#28:0",
        "o": "#10:0"
      },
      {
        "p": {},
        "r": "#58:0",
        "t": "IS_MEMBER_OF",
        "i": "#28:0",
        "o": "#13:0"
      },
      {
        "p": {},
        "r": "#51:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#31:0",
        "o": "#13:0"
      },
      {
        "p": {},
        "r": "#58:0",
        "t": "IS_MEMBER_OF",
        "i": "#28:0",
        "o": "#13:0"
      }
    ]
  },
  "user": "root",
  "version": "22.11.1 (build 8c5ff1d46513ac0b324e45f7f59f1a42150dd471/1670448994340/main)"
}

[lvca]

The graph mode returns all the edges connected. It's useful, mostly, for rendering. What you're looking for here, I guess, is only the returned records from Cypher that you can actually find under "records" property in the JSON. Could you please execute the same query with "record" mode instead of "graph"?

[artturimatias]

Thanks Luca for watching this.
I wasn't accurate with my original question. What I need is:
"Get all project coordinators, their projects and render result as a graph without any extra edges"

So edge filtering is needed for rendering purposes. In my app, the graph is part of the user interface and it should be as clean as possible.
Could this be optional query parameter?

EDIT. Maybe its good to mention that if one tries this in Neo4J UI you actually get all the edges, but that's done with extra query in the UI. There's option where you can turn this feature off.

[lvca]

@artturimatias I see now, thanks for the clarification. We could introduce a new serializer that strictly serializes the resultset in vertices and edges properties. Who can come up with a nice name? "graph" is already taken. We should rename "graph" in "studio" but we'd break the compatibility with the existent codebase. What about:

• strictgraph
• graph!
• !graph
• resultset-graph

[artturimatias]

"strictgraph" sounds meaningful to me.

[lvca]

I was able to implement "strictgraph" (if anyone comes up with a better name, I'd be glad to rename it) and with that query I didn't see any edge:

MATCH (p:Person)-[:IS_COORDINATOR_OF]->(pr:Project) RETURN p, pr

That's because edges were not part of the result set. If you do this with the new "strictgraph" works:

MATCH (p:Person)-[e:IS_COORDINATOR_OF]->(pr:Project) RETURN p, pr, e

Also, in this mode the "record" attribute is not filled up, just "vertices" and "edges" resulting in a much lighter JSON.

@artturimatias WDYT?

[lvca]

This is the JSON with "strictgraph":

{
  "result": {
    "vertices": [
      {
        "p": {
          "name": "Bob"
        },
        "r": "#25:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Bob's Project"
        },
        "r": "#49:0",
        "t": "Project",
        "i": 2,
        "o": 0
      },
      {
        "p": {
          "name": "Bob"
        },
        "r": "#25:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Bob's Project"
        },
        "r": "#49:0",
        "t": "Project",
        "i": 2,
        "o": 0
      },
      {
        "p": {
          "name": "Jenny"
        },
        "r": "#28:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Jenny's Project"
        },
        "r": "#52:0",
        "t": "Project",
        "i": 2,
        "o": 0
      },
      {
        "p": {
          "name": "Jenny"
        },
        "r": "#28:0",
        "t": "Person",
        "i": 0,
        "o": 2
      },
      {
        "p": {
          "name": "Jenny's Project"
        },
        "r": "#52:0",
        "t": "Project",
        "i": 2,
        "o": 0
      }
    ],
    "edges": [
      {
        "p": {},
        "r": "#73:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#49:0",
        "o": "#25:0"
      },
      {
        "p": {},
        "r": "#74:0",
        "t": "IS_COORDINATOR_OF",
        "i": "#52:0",
        "o": "#28:0"
      }
    ]
  },
  "user": "root",
  "version": "22.12.1 (build 08eb71f7264ba1eacd872632dcd2162765ddb67e/1671833658668/main)"
}

[lvca]

It's now in the main branch. Please let me know when you have time if this is what you were looking for or if anything else is missing.