As said in the other thread, you're missing the option subj1
predicate1 object1 and subj1 predicate2 object1.

That makes it a multi-graph.

On Thu, Apr 19, 2012 at 1:22 PM, Benjamin Heitmann (Commented) (JIRA)
<> wrote:
>    [ 
>  ]
> Benjamin Heitmann commented on GIRAPH-170:
> ------------------------------------------
> Regarding GIRAPH-141,
> I don't think that true multigraph support is required for Giraph in order to 
> use RDF data.
> If I have "subject1 predicate1 object1" and "subject1 predicate1 object2", 
> then there will be a total of three vertices with 2 edges, without any 
> conflict. If I have the same triple "subject1 predicate1 object1" two or more 
> times, then the RDF semantics document states that all of these triples refer 
> to the same two vertices and the edge between them in the RDF graph. So there 
> is no need for a multigraph again.
> If we introduce literals into the mix, then we have the same thing as above, 
> if each literal will be presented by its own Giraph vertex.
> I am not sure if I missed anything, but multigraphs dont seem to be the issue 
> here, neither in theory, nor for my already working code.
> An issue which would be more important, is the capability to retrieve and 
> modify an already created node from inside the TextVertexInputFormat class 
> (as explained above).
>> Workflow for loading RDF graph data into Giraph
>> -----------------------------------------------
>>                 Key: GIRAPH-170
>>                 URL:
>>             Project: Giraph
>>          Issue Type: New Feature
>>            Reporter: Dan Brickley
>>            Priority: Minor
>> W3C RDF provides a family of Web standards for exchanging graph-based data. 
>> RDF uses sets of simple binary relationships, labeling nodes and links with 
>> Web identifiers (URIs). Many public datasets are available as RDF, including 
>> the "Linked Data" cloud (see ). Many 
>> such datasets are listed at
>> RDF has several standard exchange syntaxes. The oldest is RDF/XML. A simple 
>> line-oriented format is N-Triples. A format aligned with RDF's SPARQL query 
>> language is Turtle. Apache Jena and Any23 provide software to handle all 
>> these;
>> This JIRA leaves open the strategy for loading RDF data into Giraph. There 
>> are various possibilites, including exploitation of intermediate 
>> Hadoop-friendly stores, or pre-processing with e.g. Pig-based tools into a 
>> more Giraph-friendly form, or writing custom loaders. Even a HOWTO document 
>> or implementor notes here would be an advance on the current state of the 
>> art. The BluePrints Graph API (Gremlin etc.) has also been aligned with 
>> various RDF datasources.
>> Related topics: multigraphs 
>> touches on the issue (since we can't currently easily represent fully 
>> general RDF graphs since two nodes might be connected by more than one typed 
>> edge). Even without multigraphs it ought to be possible to bring RDF-sourced 
>> data
>> into Giraph, e.g. perhaps some app is only interested in say the Movies + 
>> People subset of a big RDF collection.
>> From Avery in email: "a helper VertexInputFormat (and maybe 
>> VertexOutputFormat) would certainly [despite GIRAPH-141] still help"
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   Claudio Martella

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