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From Ankur Dave <ankurd...@gmail.com>
Subject Re: Incrementally add/remove vertices in GraphX
Date Wed, 19 Mar 2014 01:43:40 GMT
As Matei said, there's currently no support for incrementally adding
vertices or edges to their respective partitions. Doing this efficiently
would require extensive modifications to GraphX, so for now, the only
options are to rebuild the indices on every graph modification, or to use
the subgraph operator if the modification only involves removing vertices
and edges.

However, Joey and I are working on GraphX streaming, which is currently in
the very early stages but eventually will enable this.

Ankur <http://www.ankurdave.com/>


On Tue, Mar 18, 2014 at 3:30 PM, Matei Zaharia <matei.zaharia@gmail.com>wrote:

> I just meant that you call union() before creating the RDDs that you pass
> to new Graph(). If you call it after it will produce other RDDs.
>
> The Graph() constructor actually shuffles and “indexes” the data to make
> graph operations efficient, so it’s not too easy to add elements after. You
> could access graph.vertices and graph.edges to build new RDDs, and then
> call Graph() again to make a new graph. I’ve CCed Joey and Ankur to see if
> they have further ideas on how to optimize this. It would be cool to
> support more efficient union and subtracting of graphs once they’ve been
> partitioned by GraphX.
>
> Matei
>
> On Mar 14, 2014, at 8:32 AM, alelulli <alessandro.lulli@gmail.com> wrote:
>
> > Hi Matei,
> >
> > Could you please clarify why i must call union before creating the graph?
> >
> > What's the behavior if i call union / subtract after the creation?
> > Is the added /removed vertexes been processed?
> >
> > For example if i'm implementing an iterative algorithm and at the 5th
> step i
> > need to add some vertex / edge, can i call union / subtract on the
> > VertexRDD, EdgeRDD and Triplets?
> >
> > Thanks
> > Alessandro
> >
> >
> >
> > --
> > View this message in context:
> http://apache-spark-user-list.1001560.n3.nabble.com/Incrementally-add-remove-vertices-in-GraphX-tp2227p2695.html
> > Sent from the Apache Spark User List mailing list archive at Nabble.com.
>
>

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