DQP Distributed Query Process

Introduction

The purpose of this extension if to allow to split a SPARQL request and execute its subparts on various SPARQL endpoints.

Comparison between a local request and a distributed request

Local Request

import fr.inria.edelweiss.kgram.core.Mappings;
import fr.inria.edelweiss.kgraph.core.Graph;
import fr.inria.edelweiss.kgraph.query.QueryProcess;
import fr.inria.edelweiss.kgtool.load.Load;

Collection<String> queries = ...;
Graph graph = Graph.create();
QueryProcess exec = QueryProcessDQP.create(graph);
Load ld = Load.create(graph);
ld.load( data_uri );

for (String q : queries) {
  Mappings results = exec.query(q);
}

Distributed Request

The main difference is on the exec object, which is of QueryProcessDQP type instead of QueryProcess.

import fr.inria.acacia.corese.exceptions.EngineException;
import fr.inria.edelweiss.kgdqp.core.Messages;
import fr.inria.edelweiss.kgdqp.core.ProviderImplCostMonitoring;
import fr.inria.edelweiss.kgdqp.core.QueryProcessDQP;
import fr.inria.edelweiss.kgdqp.core.Util;
import fr.inria.edelweiss.kgdqp.core.WSImplem;
import fr.inria.edelweiss.kgram.core.Mappings;
import fr.inria.edelweiss.kgraph.core.Graph;
import fr.inria.edelweiss.kgraph.query.QueryProcess;
import fr.inria.edelweiss.kgtool.load.Load;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.logging.Level;
import org.apache.commons.lang.time.StopWatch;
import org.apache.log4j.Logger;
	
Graph graph = Graph.create(false);
QueryProcessDQP execDQP = QueryProcessDQP.create(graph, sProv, true);
execDQP.setGroupingEnabled(true); // @ToBeDocumented
execDQP.addRemote(new URL(...), WSImplem.REST);
for (String query : queries) {
  Mappings map = execDQP.query(query);
}