Foreach edge export the vertices id's to csv

[Jamie Scott]

Trying to write a simple gremlin script to take all the edges from:

g.V().outE('FOLLOWS')

and write all the vertices id's to a csv file.

vid1,vid2

vid1,vid2

What is the most efficient way to loop through and export using gremlin on a massive graph?

Thanks

[Daniel Kuppitz]

Can you define "massive graph? How many vertices / edges?

Cheers,

Daniel

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[Jamie Scott]

The graph has about 500 million vertices and over a billion edges. Not counted.

Can't seem to get the id's only.

So far:

g.V().as('from').outE('FOLLOWS').inV().as('to').select('from','to')

Will probably just use file.append once I can just return a line with the 2 id's

Thanks

[Daniel Kuppitz]

Ok, that's huge, I was expecting a much smaller graph. A BulkDumpVertexProgram is still on our TODO list:

https://issues.apache.org/jira/browse/TINKERPOP3-320

Unfortunately, I can't think of a nice way to do it with the tools that we currently have.

Cheers,

Daniel

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[Jamie Scott]

In fairness it will be a subset but still large.

Whats the most efficient way of looping through all the edges and just echoing the adjacent vertices id's out using groovy?

Cheers

[Daniel Kuppitz]

Yea I would try that first. Something like:

new File('/tmp/result.txt').withWriter { def w ->

  g.V().has("foo","bar").outE().each { def e ->

    w << e.outVertex().id() + "\t" + e.inVertex().id() + "\n"

  }

}

Cheers,

Daniel

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[Jamie Scott]

Cheers. 

[Jamie Scott]

14 million rows in a a couple of minutes. That will do nicely !