All possible paths with directions and huge estimated rows!

Neo4j Graph Platform
1

Hi

we have some data about some nodes that nodes connected to each other with relations we called them ( cable )

the number of nodes is : 349 and the number of cables is : 924

we need to find possible path ( not shortest ) between two nodes and used this :

MATCH p=(n:location)-[*]-(m:location)
WHERE n.lo_id = 70 AND m.lo_id = 486
AND ALL(x IN NODES(p) WHERE SINGLE(y IN NODES(p) WHERE y = x))
return p

but it's failed . i used to explain and saw in plan that in "VarLengthExpand(Into)@neo4j" about

67,837,845,872,747,150,000 estimated rows !!!

what's wrong with this query ?

i'm newbie with neo4j . should i put index on fields or rewrite query ?

would you please help me to make it work and find possible path with a good query between nodes ?

Cypher version: CYPHER 4.4, planner: COST, runtime: INTERPRETED.

2

Try this: I created this scenario

[location:node1] --cable-->[joint:nodex1]--cable-->[location:node2]--cable-->[location:node3]

match (a:Location {id:10})

CALL apoc.path.spanningTree(a, {}) YIELD path

return path
Result:

Screen Shot 2022-06-28 at 3.53.12 PM.png

3

Hello @mohsenshahbazi ‌😊‌

What is the objective of the WHERE clause in your query?

Why don't you specify a relationship type?

Do you have multiple node types?

My first advice is to use apoc.path.expandConfig() procedure but I need more information on your graph model to help configuring it.

MATCH (n:location {lo_id: 70})
MATCH (m:location {lo_id: 486})
CALL apoc.path.expandConfig(n, {
    terminatorNodes: [m]
})
YIELD path
RETURN path;

You can specify uniqueness property in the procedure to make sure you don't have duplicates nodes in your path.

Regards,

Cobra

4

Hi Cobra , thanks for reply

"What is the objective of the WHERE clause in your query?"

i had may paths that repeated start or end node in path so searched in google and found this where in stackoverflow to prevent appearance of repeated nodes in path .

"Why don't you specify a relationship type?"

because i have 1 type of relationship just cable .

[location:node1] --cable-->[joint:nodex1]--cable-->[location:node2]--cable-->[location:nodeN]--cable-->...[end]

"Do you have multiple node types?"

yes . 'location' and 'joint' .

i tried to use allShortestPaths and apoc.allSimplePaths but this alogs just show paths contains location not joints .

5

This query should do what you want then:

MATCH (n:location {lo_id: 70})
MATCH (m:location {lo_id: 486})
CALL apoc.path.expandConfig(n, {
    relationshipFilter: "cable>",
    terminatorNodes: [m],
    uniqueness: "NODE_GLOBAL"
})
YIELD path
RETURN path;
6

thanks a lot . it's working most of things i want . but it's not include joints node type in path and also it's returned just 1 path . i know between number of paths between this nodes is at least 6 .

edited : wanted to thank you pointed to expandConfig . reading documentation is helping a lot to underestand what you wrote .

7

Hi @mohsenshahbazi ,

Try with uniqueness set to : NODE_PATH

8

Can you share a code to create the same database to try on my side? It will be easier for me to provide you the right solution:)

9

tried NODE_PATH but still doesn't include joint node type in path . just location node types .

10

is there any way that i can export data like sqldump that you can import and check this out ?

edit : i found a way to export as csv ( apoc.export.csv.all ) . is it ok ?

11

Something more like this.

12

i made it . how i can send it ? uploaded to dropbox

13

You can change the extension of the file to .txt to upload it here I guess.

14

thanks for reply . it's just a sample of schema . here is full db export that i used

Download

15

Thank you @mohsenshahbazi :slightly_smiling_face:

For me, 70 and 486 are neighbors so how do you find 6 paths between these nodes?

Regards,

Cobra

16

correct lo_id numbers is : start :69 | end : 489

17

This query returns 6 paths:

MATCH (n:location {lo_id: 69})
MATCH (m:location {lo_id: 489})
CALL apoc.path.expandConfig(n, {
    relationshipFilter: "cable>",
    terminatorNodes: [m],
    uniqueness: "NODE_PATH"
})
YIELD path
RETURN path;

Regards,

Cobra

18

Yes . it is . but there is no joint in path .

here is a possible path that is not in result :

lo_id : 69 -> jo_id : 275 -> lo_id : 70 -> lo_id : 489
or
lo_id : 69 -> jo_id : 275 -> lo_id : 70 -> lo_id : 486 -> lo_id : 489
this query just using location type nodes . not joints . and i said at least 6 paths in the way ( it was 1 path )

19

The node jo_id 275 has a relation with lo_id 70 but it's not in the right direction. Do you want do have directed path or you don't care about the direction?

I advice to use the direction or you will have the same original issue. What is the use case at the end?

20

i don't care about direction i just care about connection between nodes . i was used allShortestPath and it was bidirectional but i couldn't resolve all possible path from that . is it possible to make it happen in this way or should we make double cable relationship between nodes in both direction to prevent this problem ?

i can make the cable from/to this joint but the database will have data redundancy and half of relationship data is just for prevent a simple problem .