Bug: [Recursive relationship] Error: Runtime exception: Internal ID of relationship is not scanned. This should not happen.

[sapalli2989]

Kùzu version

nightly

What operating system are you using?

Fedora 39

What happened?

With demo dataset execute following query:

MATCH p = (u:User {name: "Adam"})-[e:Follows* (r, n | WHERE EXISTS { MATCH (n)-[:LivesIn]->(:City) })]->(u2:User {name: "Noura"})
RETURN properties(nodes(p),'name'), properties(rels(p),"_label");

Error message:

Error: Runtime exception: Internal ID of relationship is not scanned. This should not happen.

(r, n | WHERE EXISTS { MATCH (n)-[:LivesIn]->(:City) }) is basically a placeholder for more complex filtering logic based on node and relation for current traversion step within a recursive MATCH pattern. It was used here as simple example and shouldn't change results, as every :User in the graph has a :City assigned. Without this clause, result is

kuzu> MATCH p = (u:User {name: "Adam"})-[e:Follows*]->(u2:User {name: "Noura"}) RETURN properties(nodes(p),'name'), properties(rels(p),"_label");
-----------------------------------------------------------
| PROPERTIES(NODES(p),name)  | PROPERTIES(RELS(p),_label) |
-----------------------------------------------------------
| [Adam,Zhang,Noura]         | [Follows,Follows]          |
-----------------------------------------------------------
| [Adam,Karissa,Zhang,Noura] | [Follows,Follows,Follows]  |
-----------------------------------------------------------

, which also would be expected for former query.

(after discussion with @andyfengHKU )

Are there known steps to reproduce?

No response

[andyfengHKU]

Hi @sapalli2989,

Sorry took a while to get on this. Once #4052 is fixed, I suggest the following rewrite

MATCH (n)-[:LivesIn]->(:City)
 WITH collect(n.name) AS names // collect names that satisfies the pattern
 MATCH p = (u:User {name: "Adam"})-[e:Follows*]->(u2:User {name: "Noura"})
 WITH properties(nodes(e),'name') AS pathNames, names, p AS path // find names without running predicate
 WITH size(pathNames) AS originalSize, size(list_filter(pathNames, x->x IN names)) AS filteredSize, path 
 WHERE originalSize = filteredSize // make sure all elements in list satisfy lambda `x IN names`
 RETURN properties(nodes(path),'name')

[ray6080]

The exception is no longer reproducible on latest master.
We can run the query as it is now.

MATCH p = (u:User {name: "Adam"})-[e:Follows* (r, n | WHERE EXISTS { MATCH (n)-[:LivesIn]->(:City) })]->(u2:User {name: "Noura"})
RETURN properties(nodes(p),'name'), properties(rels(p),"_label");