Find intersection and union of all directly connected vertices of a given set of vertices

[Ümit Akkuş]

What is the best way to write the queries for finding the intersection and union of all directly connected vertices of a given set of vertices? We can assume that the number of vertices in the given set is around 10, and the expected number of results would be in the 10Ks.

Does it make sense to run it in one query or create 10 seperate queries, run them in parallel and join the results afterwards? What would be the differences?

[HadoopMarc]

Hi Ümit

Yes, you can write a single query for the union and a single query for the intersection.

Union (not tested):
 

g.V().hasId(1,2,3,4,5,6,7,8,9,10).both().dedup()

Intersection (not tested):

g.V().as('a').match( __.as('a').out('created').hasId(1), __.as('a').out('created').hasId(2), __.as('a').out('created').hasId(3), __.as('a').out('created').hasId(4), __.as('a').out('created').hasId(5), __.as('a').out('created').hasId(6), __.as('a').out('created').hasId(7), __.as('a').out('created').hasId(8), __.as('a').out('created').hasId(9), __.as('a').out('created').hasId(10)).select('a')

Of course, you can also write something with a loop (repeat step), but the queries above are easy to understand.

HTH,    Marc

Op maandag 19 september 2016 19:45:16 UTC+2 schreef Ümit Akkuş:

[Daniel Kuppitz]

The intersection query doesn't have to be a global graph scan.

gremlin> g = TinkerFactory.createModern().traversal()
==>graphtraversalsource[tinkergraph[vertices:6 edges:6], standard]
gremlin> ids = [1,4,6]
==>1
==>4
==>6

gremlin> // union
gremlin> g.V(ids).both().dedup()
==>v[3]
==>v[2]
==>v[4]
==>v[5]
==>v[1]

gremlin> // intersection
gremlin> matchPatterns = ids.tail().collect {__.as("a").both().hasId(it)}.toArray() as Traversal[]
==>[StartStep@[a], VertexStep(BOTH,vertex), HasStep([~id.eq(4)])]
==>[StartStep@[a], VertexStep(BOTH,vertex), HasStep([~id.eq(6)])]
gremlin> g.V(ids.head()).both().dedup().match(matchPatterns).select("a")
==>v[3]

Cheers,

Daniel

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[HadoopMarc]

Ooh, beautiful!

Marc

Op maandag 19 september 2016 19:45:16 UTC+2 schreef Ümit Akkuş:

What is the best way to write the queries for finding the intersection and union of all directly connected vertices of a given set of vertices? We can assume that the number of vertices in the given set is around 10, and the expected number of results would be in the 10Ks.