SPARQL federated query not working

问题

My basic issue is: I have two computers A and B with Virtuoso installed and I am trying to query from one computer to the next. I created an RDF graph on machine A and executed a query on A to see the locally stored data.

sparql SELECT ?a ?b ?c
FROM <http://localhost:8890/test>
OPTION (get:soft "soft", get:method "GET")
WHERE {?a ?b ?c};

It returned the data correctly. I run the following query on machine B

sparql SELECT ?a ?b ?c
FROM <http://ipAddressOfA:8890/test>
OPTION (get:soft "soft", get:method "GET")
WHERE {?a ?b ?c};

I get a long pause and eventually get the following error
"Error HTCLI: [OpenLink][Virtuoso ODBC Driver][Virtuoso Server]HC001: Connection Error in HTTP Client"
Do I have to set up permissions for the other computer or something? Excuse me I am new to this.

回答1:

There might be a problem in your choice of the graph-name http://localhost:8890/test on your machine B.

Since the graph is not necessarily a valid Internet-resource you can not just exchange localhost with your ip-address.

Example: you could also choose a graph-name like <htw.my.own.graph> -> your graph-name is not relative to your ip-address.

来源：https://stackoverflow.com/questions/22409110/sparql-federated-query-not-working